Aspire—Fall 2008 - Aspire - The Concrete Bridge Magazine

THE CONCRETE BRIDGE MAGAZINEFALL 2008www.aspirebridge.orgPomeroy-Mason BridgeOhio to West VirginiaI-35W St. Anthony Falls BRIDGEMinneapolis, MinnesotaBig Cottonwood canyon loop road bridgeSalt Lake City, UtahU.S. Route 17 washington bypassBeaufort County, North CarolinaLIME KILN BRIDGEWinooski River George, VermontRussian RIVER BRIDGESonoma County, CaliforniaN.H. ROUTE 10 Bridge Over Mink BrookHanover, New Hampshire

Environmental Benefits of Sustainable Concrete Bridges8Photo: URS.FeaturesCONTENTSURS—A Century of Versatility 8Using expertise gained from a 100-year historywith all types of bridges to meet owners’ needs.Concrete Reuse and Recycling onOregon’s Bridge Program 20New life in old material.I-35W St. Anthony Falls Bridge 24Planning the replacement.I-35W St. Anthony Falls Bridge 28Soaring across the Mississippi River.Big Cottonwood Canyon Loop Road 36Box beams bend bridge.U.S. Route 17 Washington Bypass 40Technology driven.Lime Kiln Bridge 44Repeating history.The Russian River Bridge 48Emergency replacement.N.H. Route 10 Bridge Over Mink Brook 54Precast design meets tight schedule.DepartmentsEditorial 22420Photo: ODOT.Reader Response 4Concrete Calendar 6Perspective—EnvironmentalBenefits of Concrete Bridges 16Buyers Guide 34Photo: ©FIGG.Aesthetics Commentary 39Advertisers Index 47Concrete Connections 58FHWA—Enhancing the Environment 60STATE—Long-Span Precast U-Girdersin Colorado 6436COUNTY—Franklin County, Ohio 67AASHTO LRFD Specifications 68Photo: Michael Baker Jr. Inc.40Pomeroy-Mason BridgePhoto: URS.ASPIRE, Fall 2008 | 1

EDITORIALPhoto: Ted Lacey Photography.John S. Dick, Executive EditorThis issue of ASPIRE concludes our yearlongeffort to define sustainable issues inbridge design and construction. On page 16, CoryImhoff and David M. Taylor of HDR Inc. discuss the“environmental” aspects of sustainable concretebridges. In just the small space available, theypresent an encouraging view of the material’saccomplishments, the improvements in recentyears, and a bright outlook. This compellingnarrative is augmented with examples from recentprojects.Further reinforcing the recyclability of concrete,on page 20, Geoff Crook of the Oregon Departmentof Transportation describes his state’s dramaticprocess of putting old concrete to new uses.The article showcases for other agencies how toeffectively plan for the economical reuse of concretestructures.This issue’s featured design consultant is URS.Rooted in the past with visions to the future, URSsees opportunities in design-build, research, andnew technologies. Sustainability and creativity aresurfacing in client discussions from the beginning.Colorado is our featured state. While they havebeen relying on concrete structures for more than40 years, most applications were simple bridges withshorter spans. Exceptions began when the uniqueand exciting segmental bridges were constructed onI-70 in Glenwood Canyon and Vail Pass. Coloradohas had standards for precast concrete trapezoidalbox beams for some 15 years. More recently, theyhave produced innovations by extending spansPrecast/PrestressedConcrete InstituteAmerican Coal AshAssociationBridge Sustainability, Part Four:Environmental Considerationsthrough splicing these sections and even usingprecast trapezoidal boxes with horizontal curves!One of the most dramatic stories of concretebridges in the U.S., the I-35W replacementbridges now in their final stages of constructionin Minneapolis, begins on page 24. The bridgeswill certainly remain a standard-setting projectfor many years in the accounts of sustainabledesign and construction. The variety of challenges,including context sensitivity, speed of construction,aesthetic attributes, and durability, are skillfullydescribed in articles by Jay Hietpas of the MinnesotaDepartment of Transportation and by Linda Figgand Alan R. Phipps of FIGG.The article by M. Myint Lwin of the FederalHighway Administration traces the genesis ofthe environmental protection movement by thefederal government. On page 60, he recountswhere it began, setting the stage for theenvironmental provisions of SAFETEA-LU, whichwill be reviewed in the next issue of ASPIRE.Finally, environmental sensitivity couldn’tbe better illustrated than through the projectarticles featured in this issue. The creativesolution being used by Flatiron Constructorsfor the Washington Bypass in North Carolina(see page 40) greatly minimizes the disturbanceof sensitive wetlands. Then, the innovative useof cast-in-place concrete solves a particularlydifficult environmental challenge faced byMichael Baker Jr. engineers in Utah’s foothills(page 36).Log on NOW at www.aspirebridge.organd take the ASPIRE Reader Survey.1American SegmentalBridge InstituteExpanded Shale Clayand Slate InstitutePortland CementAssociationNational Ready MixedConcrete AssociationPost-TensioningInstituteSilica FumeAssociationWire ReinforcementInstituteExecutive Editor: John S. DickManaging Technical Editor: Dr. Henry G.RussellManaging Editor: Craig A. ShuttEditorial Staff: Daniel C. Brown, Roy Diez,Editorial Administration: James O. Ahtes Inc.Art Director: Mark Leader, Leader GraphicDesign Inc.Layout Design: Marcia Bending, LeaderGraphic Design Inc.Electronic Production: Chris Bakker,Jim Henson, Leader Graphic Design Inc.Ad Sales: Jim OestmannPhone: (847) 838-0500 • Cell: (847) 924-5497Fax: (847) 577-0129joestmann@arlpub.comReprint Sales: Mark Leader(847) 564-5409e-mail: sales@leadergraphics.comPublisher:Precast/Prestressed Concrete Institute,James G. Toscas, PresidentEditorial Advisory Board:David N. Bilow, Portland Cement Association(PCA)John S. Dick, Precast/Prestressed ConcreteInstitute (PCI)Clifford L. Freyermuth, American SegmentalBridge Institute (ASBI)Theodore L. Neff, Post-Tensioning Institute (PTI)Dr. Henry G. Russell, Managing Technical EditorPOSTMASTER: Send address changesto Aspire, 209 W. Jackson Blvd., Suite 500,Chicago, IL 60606. Standard postage paid atChicago, IL, and additional mailing offices.Aspire (Vol. 2, No. 4), ISSN 1935-2093 ispublished quarterly by the Precast/PrestressedConcrete Institute, 209 W. Jackson Blvd., Suite500, Chicago, IL 60606.Copyright 2008, Precast/Prestressed ConcreteInstitute.If you have a project to be con sidered for Aspire,send information to Aspire,209 W. Jackson Blvd., Suite 500,Chicago, IL 60606phone: (312) 786-0300www.aspirebridge.orge-mail: info@aspirebridge.orgCover: Pomeroy-Mason Bridge,Ohio to West VirginiaPhoto: URS.2 | ASPIRE, Fall 2008

Congratulations Minnesota Department of TransportationON YOUR NEWI-35W BRIDGEThe new I-35W Bridge was designed and constructed in just 11 months.The 120 precast concrete segments in the 504’main span were installed in only 47 days.New I-35W Bridge book!Opening day commemorativeedition includes:Limited edition photograph ofcompleted bridgeNearly 200 dynamic, full-color photosSmart bridge technology &sustainable designStep-by-step overview of I-35Wdesign & construction$20* plus shipping & handlingTo order call 1.800.358.3444 (FIGG)or visit www.figgbridge.com*All book proceeds benefit the Admission Possible program, which makes college admission possible for promisinglow-income students in the Greater Twin Cities, & through the ACE Mentor Program, will fund new collegescholarships for Admission Possible students who want to pursue construction & engineering careers.

READER RESPONSET H E C O N C R E T E B R I D G E M A G A Z I N Ew w w . a s p i r e b r i d g e . o r gSUMMER 2008Woodrow WilsonMemorial Bridge ReplacementWashington, D.C.HOOD CANAL BRIDGEKitsap and Je ferson Counties, WashingtonI-10 BRIDGE REPLACEMENTEscambia Bay, FloridaSOUTH FORK EEL RIVERBRIDGESLeggett, CaliforniaGARDEN GROVE BOULEVARDWIDENINGOrange County, CaliforniaPOMEROY-MASON BRIDGEOhio to West VirginiaSWINGLEY RIDGEROAD BRIDGEChesterfield, MissouriI’d like to obtain three copies of your Fall2007 issue as it contains an article aboutour Segmental Guideway for the Light Rail inSeattle.Rachel QuesinberryPCLBellevue, Wash.I would like to get more information aboutan article in the Fall 2007 issue “Short SpanSpliced Girders Replicate Historic Design.”I am looking for a copy of the contract plans.Luong TranOlympia, Wash.[Ed. Note: References were gladly provided.]What I like about ASPIRE is that itfeatures all types of bridges.Kevin NelsonCity of Saint Paul Public WorksSaint Paul, Minn.I do get [ASPIRE] magazine along with anumber of our other engineers. It is one ofthe few that actually gets read and discussedwithin our structures group.Jim DeschenesMichael Baker Jr. Corp.Salt Lake City, UtahVHB has made a few presentations andaward applications for the bridge (Lime Kiln)but having an article in ASPIRE will be adefinite highlight for the project and, I think,of interest to your readers.Chris BakerVHB-Vanasse Hangen Brustlin Inc.Bedford, N.H.I just wanted to let you know that ASPIREmagazine has aspired, pardon the pun, tomore than my expectations. It is really lookinggood.Larbi Sennour, PhD, PEExecutive Vice PresidentThe Consulting Engineers Group Inc.San Antonio, TexasBRIDGE POST-TENSIONING SYSTEMS:Innovative, Proven and Durable.SYSTEMS• BONDED MULTISTRAND• VSLAB+ ® BONDED SLABS• STAY CABLES• VIBRATION DAMPINGSERVICES• SYSTEM INSTALLATION• DESIGN SUPPORT• HEAVY LIFTING• REPAIR & STRENGTHENING• EQUIPMENT RENTALOwners and design teams rely on VSL toprovide innovative technology and provensystems to maximize the durability oftransportation structures. A world leader inpost-tensioning, VSL has evolved into a multidisciplinedbridge partner capable of providingcontractors and engineers with design support,as well as construction systems and servicesfor precast segmental, cast-in-place and staycable bridges.Congratulations on your ASPIRE Magazine.It is absolutely excellent. The Concrete BridgeIndustry has needed this for some time.Ed RiceCTS Cementwww.vsl.net • 888.489.26874 | ASPIRE, Fall 2008

LET LARSA 4D TAKE YOUR PROJECTS INTO THE NEXT DIMENSIONLARSA 4D structural analysis and designsoftware specializes in cable-stayed,suspension, and segmental bridges.FIGG turns to LARSA 4D for nonlinearanalysis, time-dependent materialeffects, and integrated modeling ofconstruction activity.LARSA software is the companystandard at FIGG, HDR, InternationalBridge Technologies, ParsonsBrinckerhoff and many other leadingengineering design companies.Veterans’ Glass City Skyway, Toledo, Ohio — FIGGBRIDGESSegmentalCompositeCable-Stayed & SuspensionPost-TensionedSteel Plate GirdersDESIGN3D TendonsInfluence SurfacesCreep & ShrinkageRelaxationLARSAAASHTO LRFD 2006 Code Check.comSusquehanna River Bridge, I-76, Pennsylvania — FIGGANALYSISGeometric NonlinearityMaterial NonlinearityFinite Element LibraryProgressive CollapseNonlinear DynamicsPlastic PushoverCONSTRUCTIONTime-Dependent MaterialsStaged ConstructionIncremental LaunchingBalanced CantileverSpan-by-SpanACCELARATED ANALYSIS & DESIGN BY LARSA 4D BRIDGE.LARSA Inc.LARSA, Inc. l WWW.LARSA4D.COMUSA: 1 800.LARSA.01 l 212.736.4326

CONTRIBUTING AUTHORSM. Myint Lwin is Directorof the FHWA Office of BridgeTechnology in Washington,D.C. He is responsible for theNational Highway BridgeProgram direction, policy,and guidance, including bridge technology development,deployment and education, and the National BridgeInventory and Inspection Standards.MANAGINGTECHNICAL EDITORDr. Dennis R. Mertz isprofessor of civil engineeringat the University of Delaware.Formerly with Modjeski andMasters Inc. when the LRFDSpecifications were first written,he has continued to be activelyinvolved in their development.Cory Imhoff is a projectmanager in HDR’s Kansas Cityoffice and specializes in thedesign and construction ofconcrete and steel bridges.Photo: Ted Lacey Photography.David M. Taylor is HDR’snational director of sustainabletransportation solutions.Frederick Gottemoeller isan engineer and architect, whospecializes in the aesthetic aspectsof bridges and highways. He isthe author of Bridgescape, areference book on aesthetics and was Deputy Administrator ofthe Maryland State Highway Administration.Dr. Henry G. Russell is an engineering consultant,who has been involved with the applications of concrete inbridges for over 35 years and has published many paperson the applications of high performance concrete.October 27-29PTI Bonded Post-Tensioning Certification WorkshopJ.J. Pickle Research Campus, The University of Texas, Austin, Tex.November 2-6ACI Fall ConventionRenaissance Grand & America’s Center, St. Louis, Mo.CONCRETE CALENDAR 2008/2009November 3-5PCI Quality Control & Assurance Personnel Training & Certification Schools andCertified Field Auditor SchoolEmbassy Suites Hotel - Nashville Airport, Nashville, Tenn.November 10-12Third North American Conference on the Design and Use of Self-ConsolidatingConcrete “SCC 2008: Challenges and Barriers to Application”Marriott O’Hare Hotel, Chicago, Ill.November 17-19ASBI 20th Anniversary International Symposium on Concrete Segmental BridgesFairmont Hotel atop Nob Hill, San Francisco, Calif.January 11-15, 2009Transportation Research Board Annual MeetingMarriott Wardman Park, Omni Shoreham, and Hilton Washington, Washington, D.C.February 3-6, 2009World of ConcreteLas Vegas Convention Center, Las Vegas, Nev.March 15-19, 2009ACI Spring ConventionMarriott Rivercenter Hotel, San Antonio, Tex.April 20-21, 20092009 ASBI Grouting Certification TrainingJ.J. Pickle Research Campus, The Commons Center, Austin, Tex.April 22-26, 2009PCI Committee DaysWestin Hotel, Chicago, Ill.May 3-5, 2009Post-Tensioning Institute Conference and ExhibitionMarriott Downtown Waterfront, Portland, Ore.May 4-7, 2009World of Coal Ash (WOCA 2009)Lexington Convention Center, Lexington, Ky.July 5-9, 2009AASHTO Subcommittee on Bridges and Structures Annual MeetingHilton Riverside Hotel, New Orleans, La.September 13-16, 2009PCI National Bridge ConferenceMarriott Rivercenter Hotel and Henry B. Gonzales Convention Center, San Antonio, Tex.October 25-27, 20092009 ASBI 21st Annual ConventionHilton Hotel, Minneapolis, Minn.November 8-12, 2009ACI Fall ConventionMarriott New Orleans, New Orleans, La.For links to websites, email addresses,or telephone numbers for these events,go to www.aspirebridge.org.6 | ASPIRE, Fall 2008

Be better at it.At URS, we believe that a successful result seldomcomes about by chance. So whether it’s an airport,bridge, highway, light rail line, health care facility orwastewater treatment plant, our determinationnever changes. To do it better. Which is why, when itcomes to the Infrastructure sector, more people areturning to us to get it done. We are the new URS.POWERINFRASTRUCTUREFEDERALINDUSTRIAL & COMMERCIALTheNewURS.com

FOCUSURS—A Century of Versatilityby Craig A. ShuttThe Big I project in Albuquerque, N.M., is the only full freeway-to-freeway interchangein the state. The $300-million project included 62 bridges and was completed ahead ofschedule and within budgetUsing expertisegained from a100-year historywith all types ofbridges to meetowners’ needsSince URS established its roots morethan a century ago, the bridge industryhas evolved and adapted to meet newneeds and challenges. The company hasdone likewise, expanding and buildingon its expertise to secure its positionas the largest bridge design firm in thecountry. While reaching those heights,the firm has tackled projects of everysize, every material, and nearly everystyle, watching trends develop alongthe way.“We have a wide experience with everytype of bridge and material, includingconcrete, steel, timber, and evencomposites,” explains Steven L. Stroh,vice president and deputy director ofsurface transportation for major bridges.“We don’t limit ourselves to one bridgetype, and we’ve handled everythingfrom simple-beam bridges to complex,cable-supported structures and evenmovable bridges; the entire gamut.”That expertise ensures the designers findthe best solution to each challenge, addsDavid Jeakle, senior structural engineer.8 | ASPIRE, Fall 2008

‘Owners are faced with very severe budgetarylimitations today, so they want durable and costeffectivebridge designs.’“We don’t have a particular productwe push; we can show strength in awide variety of structure types.” Evenso, the designers note, some materialsand styles are gaining ground today, dueto evolving technologies and owners’focus on changing needs.“Owners are faced with very severebudgetary limitations today, so theywant durable and cost-effective bridgedesigns,” says Stroh. “We have to getcreative with our design ideas, includingthe overall approach to the project.”More often today, he notes, that canmean using a design-build deliverymethod or working with a public/private partnership. “There can be verycreative contract mechanisms to stretchthe available dollars and move projectsforward before the funding actually isavailable.”Design-Build GrowingFor that reason and others, designbuildis definitely gaining supporters,he adds. “The industry is going to haveto adapt to this delivery method. It’s achallenge, but it can offer benefits toowners.” Design-build-operate formats,in which the contractor maintainsownership for some time afterward, alsoare gaining interest. “The industry isstill in the early stages of developingthese arrangements, and owners are stillexperimenting with the options, whichwill continue to play out over the nextfew years. The jury is still out on whichapproaches are more effective.”The double-deck bridge is 4040 ft long,with a cable-stayed steel main span of1410 ft and side spans featuring posttensionedconcrete box girders that wereincrementally launched into their finalposition. “The combination of materialsresulted in a very efficient and costeffectivedesign that could be completedwithin the project’s stringent time frameof 42 months from notice-to-proceedto turnover of the rail envelope fortesting,” says Stroh.The bridge, which provides 164 ft ofvertical navigational clearance, providesthree vehicle lanes in each direction onthe upper deck while the lower deckcontains dual rail-transit lines andenclosed roadways for emergencyvehicles during tropical storms. It is theworld’s largest fully enclosed, doubledeckcable-stayed bridge that carriesauto and heavy commuter rail traffic.The adjoining viaduct structure isapproximately 1630 ft long and consistsof twin six-span, cast-in-place onfalsework, multi-cell, concrete boxgirders, with span lengths of 240 to 285ft. The traffic arrangement replicates theformat for the main bridge. The viaduct’sThe cable-stayed Kap Shui MunBridge in Hong Kong, China, ispart of the crossing to the HongKong International Airport. Theside spans use post-tensionedconcrete box girders that wereincrementally launched into theirfinal position.The range of such collaborations—andthe unique designs that can be achievedusing them—can be seen in two recentexamples from the firm’s portfolio. Thecable-stayed Kap Shui Mun Bridge, withthe connecting Ma Wan Viaduct in HongKong, China, were delivered via thedesign-build method. The $250-millionstructures, part of the Lantau FixedCrossing system of toll bridges, connectHong Kong and Kowloon to Hong KongInternational Airport.ASPIRE, Fall 2008 | 9

The Arapaho Road Bridge,Addison, Tex. won a PCI2006 Design Award forBest Bridge with SpansGreater than 135 ft forextensive use of precast,prestressed U-beams anddeck panels.‘Some owners have very clear standards forwhat they want, while others rely on our expertise.’Precast concrete deck panels arebeing used to replace the deckon the Chesapeake Bay Bridge.box-girder superstructure rests on castin-placeconcrete piers that are about150 ft tall in most areas.Closer to home, the Big I project, involvingthe I-25/I-40 interchange in the heart ofAlbuquerque, N.M., features a uniquepublic/private partnership. State officialsused a new risk-management approachto obtain private industry buy-in to thepublic agency goals for the $300-millionproject, the only full freeway-to-freewayinterchange in the state.“ T h e s c h e d u l e w a s e x t re m e l yaggressive—requiring all design workto be completed in 16 months, withconstruction completed in 24 months,”says Stroh. The designers had to createa plan that could work for that timeframe, including handling traffic issues.The entire project involved 62 bridges,including eight precast concrete,segmental box-girder flyover structuresthat were the first such designs everused in the state.More than 165,000 yd 3 of concrete wereused in the total project, which includedfive miles of freeway reconstructionand 10 miles of new frontage roadsparalleling the freeway. The projectremains the largest transportationproject ever constructed in the state,and it was completed ahead of scheduleand within budget.Designs Depend onOwnersThe design approaches considereddepend on the owners’ comfort leveland familiarity with designs, notes Stroh.“Some owners have very clear standardsfor what they want, while others rely onour expertise,” he says. “Some are moresophisticated in their approach, withhuge research programs that help themcreate clear ideas of what works best forthem. There are always opportunities topromote new ideas if we can make acase, but some states are more willingto listen and learn new techniques.”Many times, designs are determinedby the local landscape, as well as localexpertise, in an effort to play to localstrengths. Similarly, states often learnnew techniques from each other, pickingup successful approaches. For the recentexpansion of the Paseo Bridge in KansasCity, Mo., for instance, the MissouriDepartment of Transportation officialsused a design-build delivery system inwhich they allowed any technologyalready used successfully in other states,even if they were unfamiliar with it.Owners are trying new techniques—and demanding more creativity fromtheir construction teams—because theirneeds are more diverse, the designerssay. “Owners’ needs are changing,”10 | ASPIRE, Fall 2008

says Jeakle. “Durability is a major issueduring the design phase, and manydecisions are being made on that basisalone.” They also want acceleratedconstruction schedules, to reduce usercosts and improve safety, while alsomaintaining good aesthetics. And,needless to say, it all must be achievedmore cost effectively than ever.Concrete More PopularFor these reasons, Jeakle sees a trendtoward the use of more concretecomponents, especially precast ones.“We’re precasting everything possibletoday: box girders, edge girders forcable-stayed bridges, pile bent caps,deck panels, footing caps, anything. Themain impetus is to minimize disruptionsfor the traveling public and shortenconstruction duration.”High-quality precast concrete componentscan be produced quickly offsite while other prep work is underway,he explains, and they can be erectedefficiently once they arrive on site. “Thegoal today is to get in, install the bridge,and get out,” he says. “The fast erectionalso can minimize labor and provide asafer environment. I’d much rather haveconstruction crews working in a welldefinedcasting yard with set proceduresthan performing work over water or livetraffic.”Creating precast concrete designs putsmore demands on the engineers duringthe design phase, he notes. “We needto know a lot more about the meansand methods that contractors use. Wehave to thoroughly understand theconstruction process.” That can meandiscussing key points, such as tolerances,weights, and delivery issues, withcontractors early in the design phase,especially for unusual structures.“The initial design fees may be higherbecause there’s more planning andcoordination work to be done early, butthat’s a small percentage of the overallcost, and that initial planning pays offwith reduced construction costs. Sothere is a net savings in the end.”Speed is a key ingredient in thewestbound Chesapeake Bay Bridgeproject currently underway. The deckon the suspension spans and throughcantilevertruss spans is being replacedwith match-cast precast concrete deckpanels that are post-tensioned together.All the work is being accomplished atnight while the westbound traffic isdiverted onto the eastbound bridge,URS is the engineer of record forthe cast-in-place segmental, cablestayedbridge across the OhioRiver between Pomeroy, Ohio andMason, W.Va.‘The goal today is to get in,install the bridge, and get out.’

The Palm Valley Bridge overthe St. John River in Floridauses spliced, post-tensionedconcrete I-girders for themain span of 290 ft.‘LEED for bridges may be coming in the nottoo-distantfuture.’A Century of DevelopmentURS Corporation’s oldest predecessor company—Greiner Engineering—was founded in1904. URS was established in 1951 and incorporated as Broadview Research in 1957. Itsmanagement developed a growth strategy 10 years later that focused on building thecompany into a multidisciplinary professional services firm. In 1968, Broadview Researchacquired United Research Inc. of Cambridge, Mass. The company’s name was changed toUnited Research Services and finally to URS.Greiner Engineering established by J. E. Greiner—a noted structural engineer—wasacquired by URS in 1996. Greiner Engineering specialized in bridge design and achievedsignificant success in its early years, and provided URS with a large measure of theirbridge design capabilities.URS has continued its policy of aggressive acquisitions and internal growth and, today,it is organized into three divisions: The URS Division provides all the services requiredto rehabilitate and expand public infrastructure, including bridges and every type oftransportation network, as well as water supply, conveyance, and treatment systems andmany types of facilities, such as healthcare complexes, schools, and courthouses. TheEG&G Division provides system engineering and technical support services to U.S. federalgovernment agencies, including NASA and the Departments of Defense, HomelandSecurity, and Treasury. The Washington Division provides engineering, construction, andtechnical services for environmental management, industrial processes, infrastructure,mining, and power projects.Overall, URS operates in more than 30 countries with more than 50,000 employees. In the2008 rankings by Engineering News-Record, it was listed as the largest engineering firmin the country and the largest bridge design firm.Its long and extensive experience in bridge design has allowed URS to maintain a staffof more than 500 structural engineers supported by an equally sized staff of CADDstructural draftsmen and technicians. The firm also has more than 35 off-the-shelf andproprietary software-application packages specifically created for designing bridges andstructures.with the bridge reopening at 5 a.m.each day. Included in the work is theinstallation of a new deck-joint systemand an aerodynamic-stabilization systemfor the main suspension spans.Design Options ExpandAnother tool being used more often isthe spliced concrete girder, says Jeakle.“For many of our projects today, ownersare requiring at least one segmentalalternative be considered during thepreliminary phase,” he says. “Previously,we’d create one only in specialsituations. It’s becoming very popular.”Stroh adds, “It’s an economical way tocreate relatively long spans. We havedesigned spliced concrete I-girder spansas long as 290 ft, and that’s an attractivealternative to steel bridges.”The firm has designed a plethora ofsegmental concrete and splicedgirderconcrete structures across thecountry, including the segmental boxgirders used in the Big I interchangein Albuquerque, N.M.; two segmentalconcrete box-girder bridges designedfor the I-35 Crosstown connectorproject in Minneapolis, Minn.; eightsegmental concrete bridges createdfor the Palmetto/Dolphin Interchangeproject in Miami, Fla.; and the spliced,post-tensioned concrete, I-girder design,complete with a 290-ft main span, forthe Palm Valley Bridge over the St. JohnsRiver in Florida.“Overall, I do believe we’re creatingmore concrete bridges today than anyother kind,” says Jeakle. “When weprovide steel and concrete alternativesfor long-span bridges, the steelalternative may be more competitive12 | ASPIRE, Fall 2008

at first, but the owners have recentlybeen selecting the concrete designdue to its durability and minimal longtermmaintenance. It’s challenging toquantify life-cycle costs appropriatelyversus in-ground costs, but whensteel and concrete are reasonably costcompetitive, more clients are choosingthe concrete alternative. They have themoney to build the bridge but not tomaintain it. They want something todaythat is less maintenance intensive.”Encouraging New IdeasFor that reason alone, URS’ designerscontinue to stay abreast of newtechniques and new ideas. These comefrom their suppliers, owners, and theirown efforts, which are funneled intotheir Center of Excellence in Tampa, Fla.,where both Stroh and Jeakle work.URS’ designers, for instance, currentlyare conducting experiments with theFlorida Department of Transportationand the University of Southern Floridaon double-composite box girders.The girders feature a steel box sectionwith a concrete slab on top, as wellas a concrete slab in the negativemomentregion on the bottom. Thegirder currently is being fatigue testedat Florida DOT’s structures laboratory inTallahassee, after which it will be testedfor serviceability and ultimate strength.“We’re always looking at new researchand new concepts,” says Stroh. “We’reseeing more places where lightweightconcrete, self-consolidating concrete,and high-strength or high-performanceconcrete can be used effectively. Wheneveranyone has something new to talkabout, we’ll listen.”The designers pick up techniquesfrom all of the company’s offices andprojects, both domestically and in theirinternational markets. “When we findtechniques that are proving successful,we bring them back and pollinate therest of our organization with them,” hesays. That distribution ensures that URSremains on the leading edge and keepsit growing no matter what challengeslie ahead.For more information on this or otherprojects, visit www.aspirebridge.org.The Isle of Palms Bridge in SouthCarolina was constructed using thetop-down approach to minimizeimpact to the pristine saltwatermarshland and shell fishery.‘Green’ Building Becoming Key“A bridge’s impact on the environment also is becoming a moresignificant factor to consider,” says Steven L. Stroh. “We’re goingto see more of a trend toward green building and using renewableresources wherever possible.” A key influence will come from theLeadership in Energy & Environmental Design (LEED) standardsestablished by the U.S. Green Building Council for buildings of alltypes. Those standards focus on energy savings, water reclamation,recycled and recyclable products, and energy used in the manufactureand transportation of construction materials.“LEED for bridges may be coming in the not-too-distant future,” hesays. URS has looked into ways to adapt the standards for bridges, headds, as more owners are expressing an interest in meeting the goals,at least as they can be translated to bridges. “We have implementedsome of the ideas they present.” Key aspects may involve salvagingmaterials from existing bridges and performing rehabilitation that willextend a bridge’s service life.“I expect that some decisions on bridge design will soon be madebased on the impact of the structure’s overall carbon footprint. Clearly,a lot of work will need to be done for that to happen, but I believewe’re headed in that direction now.”The impact on the environment has led to a variety of new erectionprocesses, including girder launchers and other techniques thatallow top-down construction to minimize disruptions to the land andwaterways below. The firm’s work on the Isle of Palms ConnectorBridge in Charleston County, S.C., shows one way this is happening.URS led a joint venture that provided complete service, including anenvironmental impact study, for creation of one of the longest bridgesin the state.The structure provides the only access between the mainland andthe barrier island community, and was constructed after the previousaccess, via an obsolete swing bridge, was destroyed during HurricaneHugo. The 2-mile-long bridge spans a pristine saltwater marshland andshell fishery. “The prescribed environmental conditions required thatwe keep construction out of the waterway,” Stroh explains.To achieve that, the design used precast, prestressed concrete I-girders,which were erected using a work bridge that only touched the pilingswithin the tight environmental requirements. Completed in 1993,it was one of the first projects to use this approach, providing thetop-down construction that left the waterway intact. “This solutionis being use more today in these situations, as are gantries and othertechniques,” he says. “It gives us one more tool in our tool box.”ASPIRE, Fall 2008 | 13

“Future Technology forConcrete Segmental Bridges”NOVEMBER 17-19, 2008Fairmont Hotel, San Francisco, CANOW AVAILABLE: Online SymposiumRegistration, Brochure, and Exhibitand Hotel Reservations Information.photo courtesy of Kiewit Pacific Companywww.asbi-assoc.org/news/symposium/11188 ASBI Aspire Ad.indd 1 5/29/08 11:33:15 AMPhotos courtesy of CaltransNew Benicia-Martinez BridgeBenicia, CaliforniaBuilt to withstand earthquakesin a high-seismic zone, thenew five-lane, 7,400-ft.Benicia-Martinez Bridge isa lifeline structure for SanFrancisco Bay Area residents,a challenging designation fora bridge with such long spanlengths. To learn more, visitwww.tylin.com/ads.Two Harrison Street, Suite 500, San Francisco, California 94105tel: 415.291.3700 | fax: 415.433.0807 | www.tylin.comad_aspire_mag_7x4.625in_v04.indd2 214 | ASPIRE, Fall 200812/13/2007 11:07:38 PM

PERSPECTIVEENVIRONMENTAL Benefits of Concrete BridgesEvery day, sustainability becomes an all-encompassing conceptthat applies to every aspect of the design and construction ofall structures; concrete bridges are no exception. Sustainabilityaddresses the “triple bottom line”—environment, community,and economy. By balancing the three, the needs of present andfuture generations can be met. This article focuses on the effectsconcrete bridges may have on the environment—are they good toand good for the environment?Concrete is a Sustainable MaterialThe primary raw material used to create cement is limestone, which is abundant. Concrete is madeeven more sustainable by the use of fly ash, which is recycled waste material from coal-fired powerplants. Fly ash has been used this way for many years, and most projects in the United States todayinclude fly ash in the concrete. Other recycled cementitious materials include blast furnace slag andsilica fume. Reinforcing steel and prestressing strands are also recyclable materials. The portlandcement industry is a leader in protecting the environment and promoting sustainability. The industryhas reduced emissions by 33% since 1975 and plans to voluntarily reduce CO 2emissions to 10%below the 1990 baseline. Concrete uses recycled materials, abundant materials, and environmentallyconscious manufacturing processes while providing the bridges that our communities need anddepend on for transportation, commerce, and quality of life.Concrete is RecyclableProducing only as much concrete as is needed for a project reduces waste. And when a concrete bridgehas reached the end of its useful life, the concrete can be recycled by crushing it and using it as fill forroads. In addition to reducing waste in landfills, this approach reduces the need to mine and processnew materials and limits pollution involved in transporting material to sites. An example of this type ofmaterials management can be found in the article on page 20 about Oregon’s bridge program.As another example, after the Arthur Ravenel Jr. Bridge was constructed in Charleston, S.C., more than248,000 tons of concrete were salvaged from demolition of the two structures it replaced. The materialwas used to create 82 acres of reef habitat.16 | ASPIRE, Fall 2008

Photo: Scott Dobry.by Cory Imhoff and David M. Taylor, HDR Inc.Concrete Creates Long-Lasting StructuresConcrete can withstand a wide range of environmental challenges, fromtemperature extremes to corrosive environments. Concrete is made even strongerthrough the use of the previously mentioned recycled cementitious materials. Asa result, concrete bridges can have service lives approaching or exceeding 100years.The concrete industry is continually improving material quality and capabilities,and bridge designers are finding new and innovative ways to use these materials.For example, the advent of high-performance concrete (HPC) has resulted inlonger spans, taller towers, better decks, and safer, more durable structures. Withthese improvements, even more sustainable solutions can be developed.The use of prestressed concrete is a longstanding practice in the bridge industry.This technology improves the performance and longevity of concrete bridgesby maximizing what concrete does best—resisting loads via compression.Pre-tensioned and post-tensioned concrete bridges are extremely resilient todeterioration, even when subjected to the harshest environments. Longer spansand better, more sustainable bridges are created with the use of prestressingtechnologies.The curved architecture of the new Memorial Bridge in Clearwater, Fla., reflects thesunset to accent its scenic setting along the Intracoastal Waterway. Photo: HDR Inc.Concrete from the Arthur Ravenel Jr.Bridge in Charleston, S.C., was givennew life as artificial reef habitat.Photo: HDR Inc.Fiber reinforced plastic (FRP) reinforcementis becoming more availableand brings the potential to furtherenhance the performance of concretebridges. Trading the traditional steelreinforcement bar for an FRP bareliminates the expansion that comeswith corrosion of an embedded steelreinforcing bar. This is the most commonform of distress and deteriorationobserved in reinforced concrete bridges.As the use of FRP bars increases, thereputation of concrete as an alreadygreat sustainable material is sure togrow even more.From the outset, the concrete industry,including concrete producers, designers,contractors, and precasters, hascontinually aspired to find new andbetter ways to use and improve thismaterial. From plain concrete to thedevelopment of reinforced concrete tothe use of HPC with prestressing andFRP bars, the efforts continue. Moreadvancement is sure to come and willfurther improve the longevity andsustainability of concrete bridges. Forexample, the Massachusetts Instituteof Technology has been applyingnanotechnology to concrete todetermine whether it’s possible to bothimprove concrete performance andreduce carbon-dioxide emissions duringits production.ASPIRE, Fall 2008 | 17

The use of 183-ft-longprecast, prestressedconcrete beamsacross the UnionPacific Railroad trackseliminated the needfor intermediatebents. A similardesign was used forthe 162.5-ft-longAlder Creek Bridge toeliminate foundationsin the water.Photo: HDR Inc.Improvements inTechnology EnhanceEnvironmental MitigationEffortsMinimizing environmental impactsduring construction is nothing new.What is new is that innovations inconcrete are making this easier toaccomplish. Issues such as minimizingstream disruption and wetland displacement,accommodating seasonalmigratory patterns, and reducing sideslope erosion are all possible withconcrete bridge structures.Furthermore, concrete makes it possibleto facilitate accelerated construction;thereby, reducing greenhouse gasemissions caused by traffic delays andconstruction equipment operation.The Federal Highway Administration’sHighways for LIFE program supportsthis initiative by contributing fundsfor accelerated construction projects.Prefabricated concrete componentsare the heart of the accelerated bridgeconstruction trend as illustrated by thefollowing examples.One of the projects in the OregonTransportation Investment Act III StateBridge Delivery Program involved U.S.26 at Alder Creek. The contractor used162.5-ft-long beams to create a singlespanstructure over the creek. Thisdesign approach eliminated the need forfoundations in the water, causing lessdisruption to the natural setting. Usingthe big-beam technology also reducedthe time needed for construction,speeding up the return to normal trafficoperations. By reducing environmentalimpacts and saving time and money, thisuse of a concrete design addressed allcomponents of the triple bottom line.For the project to replace the 24th StreetBridge over I-80/I-90 in Council Bluffs,the Iowa Department of Transportationhad to consider the effect lengthyclosures would have on the surroundingbusiness corridor. Retail, casino, lodging,and recreational businesses in the areadepend on traffic entering and exitingvia the 24th Street interchange. Aprecast concrete deck system acceleratedthe schedule and made it possible tostage construction to allow at leastthree lanes of traffic to remain open atall times. As a result, the communitywill benefit from reduced impacts totraffic and the economic well-being ofthe local businesses.Concrete is a CompatibleMaterialWhile much attention goes to thenatural environment, the built, historic,and cultural environments must beconsidered. Compatibility may beexpressed in terms of aesthetic value,community acceptance, or historicalsignificance. Some concrete bridgesare viewed as landmarks in theircommunities and include architecturalornamentation that adds drama andinterest. Advancing technologies createnew opportunities for concrete bridgesto add to the built and historic fabric ofour communities.The new Clearwater Memorial Bridgein Florida employs a curved architectureto reflect the sunset from the structureand accent its setting. Additionally, thechosen alignment through downtownallowed efficient traffic movementwhile supporting continued economicdevelopment—again providing socialand economic sustainability benefits.SummaryBridge designers face a new set ofparameters today. Beyond the questionof economics and functionality, theymust ask themselves whether theirdesigns will be long-lasting; do they helpprotect the natural environment; canthey complement the built and culturalenvironments; and can they help reducethe carbon footprint?When it comes to concrete bridges, theanswer to these questions is “Yes.”18 | ASPIRE, Fall 2008

Constructing Solutions:At BASF, we’ve built ourbusiness on the beliefthat our customersdeserve a comprehensivesolutions package. Thatis why we are constantlyintroducing new admixturetechnologies, while stayingtrue to our core mix ofknowledgeable people,performance-enhancingproducts, and superiorservice. It is what hashelped our customersbuild their success stories,and how we will continueto transform the toughestconstruction challengesinto concrete results.www.masterbuilders.com800-628-9990It’s All In The Mix.

New Life inOld Materialby Geoff Crook, Oregon Department of TransportationConcrete Reuseand Recycling onOregon’s BridgeProgramWith a 10-year duration, involving 365bridges, and costing $1.3 billion, theOregon Transportation Investment Act(OTIA) III State Bridge Delivery Programis Oregon’s largest infrastructure projectin five decades.The massive scope of the bridge programhas given the Oregon Department ofTransportation (ODOT) an opportunityto make the three “Rs” of reduce,reuse, and recycle standard practicesin bridge and highway construction.In 2005, the agency and the OregonDepartment of Environmental Qualityworked to develop a set of materialsperformance standards for use on thebridge program. These standards directcontractors to handle constructionwaste, including concrete debris, toachieve the “highest and best enduse,” preventing waste generation andminimizing disposal in landfills.According to the Construction MaterialsRecycling Association, more than 140million tons of concrete are recycledevery year in the United States. ODOTis eager to contribute to this process.Halfway through the bridge program, wealready have many successes to report.Recycling: Making the OldNew AgainFor contractors working on the bridgeprogram, the benefits of recyclingare many, such as the avoidance ofhauling costs and landfill fees. For localcommunities, recycling on site or nearbymeans less noise and truck traffic andbetter air quality. In addition, recycledor reused concrete conserves land andaggregate resources.Contractor Staton Cos. helped ODOTset the standard for success in reuseand recycling early in the program whenit demolished the Burlington NorthernSanta Fe railroad bridge in Madras andthe California Avenue and Green SpringsDrive Bridges in Klamath Falls, bothon U.S. 97. On these projects, Statonsalvaged 100% of the concrete fromthe demolitions.In Madras, almost 580 tons of concretewere delivered to Cinder Butte Rockin Redmond for crushing and reuse. InKlamath Falls, the company was able toset the bar even higher by recycling thematerial on site. It removed 7227 tons ofconcrete from two bridges and crushedit into 1-in. rubble. Five hundred tons of20 | ASPIRE, Fall 2008

On the OTIA III State Bridge DeliveryProgram, ODOT took an opportunityto capitalize on the program’s scopeand emphasized environmentalconsciousness. Because many of Oregon’sbridges are built using precast concrete,the potential for recycling and reuse istremendous. All Photos: ODOT.this gravel were then reused as fill andto pave an approach road.On a separate project near Cottage Grove,Capital Concrete Construction matchedStaton’s achievement by recycling all theconcrete from a demolished bridge intonew embankments.To give an idea of the savings involvedin avoiding disposal costs, HamiltonConstruction, which rebuilt two bridgessouth of Portland, estimates 3000 tonsof bridge demolition materials, including1000 yd 3 of concrete, were either reused(15%) or recycled (85%), resulting in anestimated savings of $120,000 in landfillfees.When they can’t use the rubble theygenerate themselves, contractors recycleby collaborating. Holm II Inc. and itssubcontractor, Goodfellow Bros. Inc.,were demolishing and rebuilding anoverpass above I-5 south of Eugene thatwould leave them with roughly 30,000yd 3 of rubble. A short distance away,Ross Bros. & Co. needed nearly 40,000yd 3 of embankment materials to usebeneath four bridges and to widen anI-5 interchange. Working together, the‘More than 140 million tons of concrete arerecycled every year in the United States.’three independent contractors agreed toexchange the aggregate free of charge.Goodfellow Bros. avoided disposal costs,and Ross Bros. avoided purchasing fill.The collaboration was made possible byODOT’s commitment to the design-buildmethod of construction, which givescontractors the flexibility to proposecreative solutions that address currentneeds, future needs, or both. On atightly packed construction schedule,this sort of collaboration keeps everyoneon time and within budget. In additionto keeping the rubble out of a landfill,Goodfellow Bros. and Ross Bros. savedmoney on transportation costs. Becausethe work sites were less than two milesapart, fuel costs and pollution weredecreased significantly.ODOT saved money through thisinitiative as well. Every constructioncontract has a clause that allows forrising fuel prices. Reusing the wastematerial and transporting it over ashorter distance reduced the amount ofmoney spent on diesel fuel, making thecontract price more stable and helpingto stay under budget.Upping the Ante: Reuse ofBridge BeamsWhile we strive to keep concrete outof landfills whenever possible, thereuse of intact bridge beams saveseven more time and money thanrecycling by avoiding the need to crushthe aggregate, as well as cast newbeams. Reuse requires creativity andODOT has been proactivelyaddressing Oregon’s agingbridges for more than six years.Oregonians have not seen aninvestment of this magnitude inhighway and bridge constructionin 50 years, since the state’sinterstate freeway system wasbuilt in the 1950s and 1960s.Of the 365 bridges in the program,119 are currently under construction,and another 76 have been completedand opened to traffic.ODOT’s 1.3 billion OTIA III StateBridge Delivery Program is replacingor repairing hundreds of bridges likethis one to ensure that motoristsand freight reach their destinationsquickly and safely.Hundreds of tons of epoxycoatedreinforcement wereused for the Green SpringsDrive Overpass on U.S. 97 inKlamath Falls, Ore. Whenthe original structures weredemolished, the contractorrecycled 100% of theconcrete.

forethought that demonstrate ODOT’sand contractors’ joint commitmentto sustainability as more than just aneconomic decision.Near Creswell, a manager from GoshenForest Products noticed constructiontaking place near his lumber mill, so heapproached the superintendent for thecontractor, Holm II, about needing somebridge beams for his lumberyard. Afterconstruction was complete, rather thandemolishing the beams and grinding theconcrete to rubble, Holm II decided totake the beams out in pieces and deliverthem to the mill.The six 105-ft-long beams and bridgedeck equate to approximately 214 yd 3of concrete that will be diverted fromlocal disposal or recycling facilities. Themill will reuse the beams in their entiretyas foundations for supporting harvestedlogs.In other cases, strategic planning leadsto thoughtful reuse of bridge beams. Astandard plan for keeping traffic movingwhen replacing an interstate highwaybridge is to install a temporary detourstructure. Because CH2M Hill wasboth the designer and the builder of10 replacement bridges on I-5 betweenEugene and Roseburg, it was able todesign an early detour structure so thatmost of its 88 prestressed concretebox beams could be reused on threesubsequent detour bridges. Because eachbeam is worth approximately $6300,reusing 80 of them reduced the cost ofthe contractor’s bid by about $500,000.As the cost of quarrying and castingconcrete beams continues to rise,it makes increasing sense to preserveOn the I-5, Clarks Branchto Tunnel Mill Race project,contractors demolishedthe River Drive overpassand salvaged 30,000 yd 3 ofrubble, which was reused asaggregate on another OTIAIII State Bridge DeliveryProgram project.Good planning on the bridge programhas allowed contractors to reuseprecast concrete beams from detourstructures. On a project near Eugene,56 precast, prestressed box beamswere salvaged from a detour structureand will be used on later projects.them for future use even when noimmediate need exists. Recently, ODOTand Hamilton Construction collaboratedto salvage 56 precast, prestressed boxbeams, each 115 ft long, from a detourbridge near Eugene and deliver them toa storage lot on the other side of thecity. With five years of bridge programconstruction ahead, we are confidentthere will be a future need for thesesalvaged beams. And when we supplythem to contractors, the state will savean estimated $1 million off the contractsin which they’re reused.Next StepsIn 2008, ODOT will include specialprovisions in construction contracts toguide and better track waste managementactivities. Construction companieswill be asked to forecast the percentageof materials they anticipate reusing orrecycling on their bridge projects andsubmit quarterly reports about theiractual progress.Targets have been established for variousmaterial types, upward of 80% forconcrete, depending on the area of thestate. To assist contractors, ODOT hasdeveloped template reuse and recyclingplans, reporting forms, and a statewiderecycling directory and guidebook.With these new tools, ODOT will beable to collect complete and accurateinformation about what is feasible. Thesedata will provide information about ourbusiness practices and help us set realisticgoals for the future. We also want tohighlight the good work that contractorsare doing on behalf of the environmentin the course of bridge repairs andreplacements.The economics of recycling concrete aremore than convincing. Crushed recycledaggregate saves money and landfill space.Reused beams recover the value of theraw materials, as well as the labor thatgoes into their long-lasting construction.And perhaps most compelling of all arethe benefits for ourselves and futuregenerations as we lessen our demand fornon-renewable natural resources.___________________On the California Avenueovercrossing project, StatonCompanies, an ODOT contractor,recycled 100% of the concrete from the demolitions.Geoff Crook is the environmental programmanager for the Oregon Departmentof Transportation’s OTIA III State BridgeDelivery Program.For more information on this or otherprojects, visit www.aspirebridge.org.

PCI Seeks a UniQue Personto Serve the Transportation CommunityPCIis the lead technical calorganization ofthe precast concrete structures industryand one of the most respected associationsin the construction field. We play apivotal role in developing new generationsof bridges, pavements, and othertransportation structures. This role willexpand considerably over the next decadeunder the leadership of a uniquelyqualified and talented individual servingas Director of Transportation Systems.For more information, please contact Jim Toscas, PCI President (jtoscas@pci.org).Your communications will remain confidential.Are yousomeone who…… is morecomfortable in front of anaudience than behind a desk?… would rather plan and conduct aconference than simply attend one?… can not only read and understanda seminal technical manual butalso organize its development?… is more drawn to leading a team orcommittee than serving on one?… is full of ideas on new ways todevelop durable, efficient, andsustainable transportationinfrastructure?… would rather guide the directionof bridge design than design abridge?… has a variety of skills and talentsthat are untapped in your presentposition?… is ready to cross a new careerbridge?If so, you may be the specialindividual that PCI seeks.MKT007_WantAd_TransDir.indd 1TAKING THE LOAD OFF…12/4/07 3:20:33 PMBridges Around the WorldSustainableSolutions forLonger LastingConcrete BridgesMore Efficient Designs– Less Concrete– Less Steel– Fewer/Smaller Foundations– Lighter for Shipping & HandlingEnhanced Durability– Less Permeable– Less CrackingVirginia Dare Bridge - North CarolinaLightweight concrete deck forentire 5.2 mile length of bridge.Bridge designed for100 year service life.HIGH PERFORMANCE LIGHTWEIGHT AGGREGATE800.898.3772 704.637.1515www.stalite.com11282_Carolina_Stalite_fall08.indd 18/26/08 4:21:47 PMASPIRE, Fall 2008 | 23

I-35W St. Anthony Falls BridgePlanning the ReplacementIn a little over 1 year since thetragic collapse of the I-35W Bridgeon August 1, 2007, two newriver crossing bridges and theirapproaches will be completedthis year. Although the contractrequires that the construction becompleted by December 24, 2008,the project was opened to trafficon September 18. The rapidreplacement of the I-35W overthe Mississippi River once againre-established the vitaltransportation link to destinationssuch as downtown Minneapolisand the University of Minnesota.SchedulePrior to Contract Awardby Jay Hietpas, Minnesota Department of TransportationThe 140,000 vehicles that used theprevious eight-lane structure had to findalternative routes. The impact resulted inadditional congestion on the local andregional road system, with a daily roaduser cost of $400,000. This impact valuedoes not include the economic impactresulting from the closure of I-35W.Moving forward with the rebuildingeffort was much more complex thansimply replacing the structure. Theroadway approaches did not meetcurrent capacity or design standards.A large portion of the project sitecontained contaminated materials frompast industrial uses. Stakeholders andcitizen groups expressed differing viewson the visual quality approach to theproject. Site conditions included anArmy Corps of Engineers lock and damsystem, limited right-of-way to expandcapacity, six railroad tracks under thestructure, major underground utilities,and dealing with the removal of thecollapsed structure.By working closely with stakeholderswithin days of the collapse, theMinnesota Department of Transportation(Mn/DOT) rapidly defined the scope ofthe project. The new I-35W bridge wasto be reconstructed as two new riverbridges, each built to accommodate fivelanes of traffic in each direction for atotal of 10 lanes plus standard-widthshoulders. Project elements also includedimproving the geometric deficiencies inthe corridor, reconstructing the rampsat the interchanges on each side of thebridge, and accommodating a futurelight-rail transit system on the newstructure.The process was expedited in order tobegin construction prior to the winterseason. Photo: Mn/DOT.August 1August 4August 8August 8August 23September 14September 18September 18September 19October 8Bridge 9340 collapsesMn/DOT issues RFQFive teams respond toRFQMn/DOT short-lists fiveteamsMn/DOT issues RFPTechnical proposals duePrice proposals dueMn/DOT interviewsdesign-build teamsProject lettingContract executed24 | ASPIRE, Fall 2008

The new crossing consists of five lanes in eachdirection with standard width shoulders, and canaccommodate a future light-rail transit system. Rendering: © FIGG.Design-Build ProcessWithin days of the collapse, Mn/DOTbegan the process of rebuilding thisvital transportation link. To expedite theproject delivery, Mn/DOT chose to usedesign-build over a traditional designbid-buildapproach. Design-build allowedfor speed of project delivery, designflexibility, and construction innovation.Mn/DOT allowed design-build teamsto choose from seven allowable bridgetypes, propose geometric solutionsthat address current substandardelements, and develop the visual qualitycomponents to the project.The statutesrequire a two-stepprocurement process fordesign-build projects.Minnesota state statutes require a twostepprocurement process for designbuildprojects. The first step involvesshort-listing the most highly qualifiedteams in response to a Request forQualifications (RFQ). In step two, theshort-listed teams submit technical andprice proposals in response to a Requestfor Proposals (RFP). The price proposalsremain sealed until the scoring of thetechnical proposals is complete.The design-build process was expeditedin order to begin construction prior tothe winter season. On a typical Mn/DOTdesign-build project, the procurementtimeline is typically 6 to 12 months. Onthe I-35W project, letting of the contractoccurred on September 19, only 50 daysafter the collapse.Due to the expedited nature ofthis procurement process, Mn/DOThad extensive communication withthe design-build teams during thedevelopment of the design-buildRFP. Daily one-on-one meetings wereconducted with the design-build teams.These meetings allowed design-buildteams to receive real-time updates onscope changes and ask questions aboutthe project. Mn/DOT also allowed eachteam a weekly one-hour site visit. Inaddition, each design-build teamestablished a single point of contact thathad 24-hour access to Mn/DOT’s designbuildcommunication manager.In addition to extensive communicationwith the design-build teams, Mn/DOThad extensive contacts with regulatoryagencies, utilities, and impactedstakeholders during the procurementprocess. Mn/DOT secured eight outof ten regulatory permits prior toletting. The other two permits werethe responsibility of the contractor.By actively involving all the interesteddesign-build teams in the utilitycoordination process before letting,a major gas relocation line could berelocated concurrently with the designbuildprocurement process. Mn/DOTestablished a Visual Quality AdvisoryTeam (VQAT) to define the aestheticframework for the project. Design-buildteams met with the VQAT on severaloccasions to develop their aestheticapproach for incorporation into theirproposals. Coordination with the railroadallowed for the removal of five railroadtracks and shortening of the bridge.As the RFP was being developed, Mn/DOT used the goals of the project todefine how the design-build proposalswere going to be evaluated. The goalsof the project included constructing aproject safely, producing a high-qualityproject, completing construction bythe end of 2008 within the allowablebudget, allowing public input into thedesign and visual quality aspects of theproject, and addressing stakeholderconcerns throughout the project.On a traditional process, the publicinput and visual quality aspects wouldhave been addressed prior to letting. Onthis project, these processes occurredsimultaneously with the project. Manystakeholders were concerned thatthe public would not have adequateinput into the design features of thebridge. To address these concerns, Mn/DOT emphasized design flexibility tothe design-build teams. The proposedapproach was to not only obtain publicinput, but also provide a mechanism toincorporate public feedback into thedesign and construction process.During the proposal preparation process,Mn/DOT allowed each team to submit upto eight Alternative Technical Concepts(ATC). An ATC allows a team to submitan equal or greater value change to theRFP. To expedite the Mn/DOT reviewtimes, ATCs were limited to the structuraland foundation sections of the RFP. EachATC was kept confidential and not sharedbetween the competing teams.Design-build teams were allowed tosubmit a 20-page response to the RFP.In addition, 10 pages were allowed fordesign plans and 10 pages were allowedfor resumes. Four teams submittedproposals for the project.Mn/DOT had extensive communication withthe design-build teams and stakeholders.ASPIRE, Fall 2008 | 25

The winning bid included a proven approach to visual quality that allowedthe community to select several visual components of the bridge andapproaches. Rendering: © FIGG.Scoring MethodTechnical proposals were scored by asix-person evaluation panel. The averagescore of the six scoring membersfor each team became the officialtechnical score. In addition to the sixscoring members, 21 other individualsassisted with the evaluation process.The evaluation group included Mn/DOT, City of Minneapolis, the NationalPark Service, the Federal HighwayAdministration, the Association ofGeneral Contractors, and the MinnesotaDepartment of Administration.Evaluation CriteriaExperience of key individualson similar projectsDesign and constructionrelationshipsPoints2010Safety approach 10Construction quality approach 10Visual quality enhancements 10Visual quality approach withstakeholders10Roadway design elements 10Life-cycle structural designapproachPublic involvement 155In addition to the technical score, theprice and time components were alsoevaluated. In accordance with statestatutes, the selection formula consistedof cost plus time, divided by technicalscore. Design-build teams wereallowed to bid between 337 and 437calendar days to complete the project.The number of days was multiplied by$200,000 (half of the daily road usercost) and added to the price proposal.This value was then divided by thetechnical score. The lowest adjustedscore was determined as the best value.The technical scoring was completedbefore the price and time componentsfor the project were known. Thetechnical scores ranged from 55.98 to91.47, the cost ranged from $177 to$234 million, and the time componentsranged from 367 to 437 days. Thecontract was awarded to Flatiron-Manson, who had the technical scoreof 91.47, a price of $234 million, and atime component of 437 days.Although the Flatiron-Manson teamhad the highest cost and longest time,their technical approach and score wassubstantially higher than the otherproposing teams. The Flatiron-Mansonteam eliminated the six geometricdeficiencies, accommodated futureinfrastructure needs in the area, andprovided structural benefits that reducedfuture maintenance and reconstructioncosts. The Flatiron-Manson approachalso included a proven approach to visualquality that allowed the community toselect several visual components of thebridge and approaches.This project was a major engineeringchallenge for all design-build teams.With limited access to the projectsite due to the collapsed structure,the design-build teams had to rely onlimited subsurface investigation data.The project also presented majorcost and schedule risks due to utilityrelocations, unknown site conditions,and contaminated materials. Due tothese risks, construction could haveeasily extended into the summer of2009.IncentivesTo ensure that the project wouldlikely be completed in 2008, Mn/DOT offered incentives to completethe project on time. If the job wascompleted on time and the contractorwaived all outstanding claims, a $7million incentive would be paid to thecontractor. The contract also allowsearly completion incentives up to anadditional $20 million if the project iscompleted 100 days early. This incentivevalue is calculated based on half ofthe roadway user cost impacts to theproject.___________________Jay Hietpas is design-build programmanager and I-35W design-build projectoffice manager with the MinnesotaDepartment of Transportation Office ofConstruction & Innovative Contracting.For more information on this or otherprojects, visit www.aspirebridge.org.26 | ASPIRE, Fall 2008

I-35W Bridge - Minneapolis, MNPhoto by Tim Davis/Courtesy of FIGGLess than one year after the tragic collapse of the I-35W Bridge,employees cheer as a barge-mounted crane lifts the final concretesegment into place on the main span of the new I-35W Bridge. TheFlatiron-Manson joint venture expects to open the new bridge to trafficthree months ahead of schedule. The bridge took just eleven months tobuild, but the experience will undoubtedly last a lifetime. Best momentshappen all the time in people’s lives. Here at Flatiron, we’re proud tomake some of them possible.www.flatironcorp.comA HOCHTIEF Company

PROJECTI-35W St. Anthony Falls BridgeSoaring Across THEA new crossingwith sustainability,redundancy, and fastconstruction.The side spans over land were castin-placeon falsework using the samebox girder shape as the main span.Photo: Mn/DOT.Carefully planned design and constructionstrategies by the Flatiron-MansonJoint Venture, with FIGG as designer,focused on a new I-35W MississippiRiver crossing with sustainability,redundancy, and fast construction. Thismodern concrete bridge for the futuremaximized the use of local labor, localmaterials, and multiple concurrentconstruction operations to optimizeconstruction through the Minneapoliswinter.The Minnesota Department ofTransportation (Mn/DOT) set requirementsand expectations centered ona bridge life beyond 100 years. Mn/DOT’s vision allowed innovation andenhancements to traditional qualitystandards. The mission was to designand build a 10-lane wide, transit-ready,interstate bridge over the MississippiRiver, with a 504-ft-long main span, in15 months. The opening on September18 meant a design-build delivery in11 months while achieving the qualitystandards set for a long bridge life.Eight long-line casting beds wereset up for the main span segments.Photo: Mn/DOT.The bridge consists of twin 1223-ft-longconcrete structures, each 90 ft 4 in. wideusing two box girders per structure. Inaddition to crossing the river, there is anoverpass at 2nd Street, a crossing of anhistoric stone bridge abutment wall, arailroad track, hazardous materials site,multiple underground and overheadutilities, local street crossings, andNational Park Service land. Shortly afterthe October 8, 2007, Notice-to-Proceed,profileI-35W St. Anthony Falls Bridge / Minneapolis, Minn.Contractor: Flatiron-Manson (a joint venture of Flatiron Construction Corporation, Longmont, Colo., and MansonConstruction Company, Seattle, Wash. )Bridge Designer: FIGG, Tallahassee, Fla.Concrete Supplier: Cemstone Products Co., Mendota Heights, Minn.Post-Tensioning Supplier: DSI, Bolingbrook, Ill.Formwork Supplier: EFCO, Avondale, Ariz. (Segments and Piers 2 and 3); Symons, Bloomington, Minn. (Pier 4)28 | ASPIRE, Fall 2008

Main span segments were precast while sidespans were cast-in-place.Mississippi Riverby Linda Figg and Alan R. Phipps, FIGGa special design meeting, knownas a FIGG Bridge Design Charette,was held with 88 people from localcommunities, so they could choosevarious design features. They chose acurved pier shape, open railing style forvistas of the river, white bridge color,aesthetic lighting of the bridge usingLEDs, and local stone abutment walls.This community involvement took placeconcurrently with some of the design inorder to begin construction as soon aspossible. Construction could only beginafter detailed design plans had receivedthe official “Released for Construction”approval, and long lead-time itemshad to be addressed early so that allscheduling could be optimized.Building a StrongFoundationConstruction of the bridge began onNovember 1, 2007, (Day 17 from start ofconstruction) with the drilling of a test/demonstration shaft for the foundations.The team selected 7-ft- and 8-ft-diameterdrilled shafts for the main bridge pierRolling structures moved along thelong-line casting beds to provide aheated work and curing environmentduring the winter months.Photo: © FIGG.foundations. The larger shaft diametersreduced the number of constructionoperations necessary at each foundationAfter precasting, the 120 main spansegments were moved to a riversidestaging area prior to transportingby barge to the bridge site.Photo: © FIGG.and worked within the site constraints.After successful completion of the testshaft on Thanksgiving Day, four drill rigswent to work at multiple locations. Atotal of 40 shafts up to 95-ft deep andsocketed into rock support the mainbridge piers. An additional sixty-nine4-ft-diameter shafts up to 27-ft longsupport the north abutment and the2nd Street overpass, north of the mainbridge. To speed placement and achievea monolithic, high-quality concrete, selfconsolidatingconcrete (SCC) was usedin the shafts. The SCC mix, supplied byCemstone Products, obtained better thanexpected strengths. The design called for5000 psi compressive strength concrete.Actual strengths averaged 8360 psi at28 days. At 56 days, strengths of 9890Segmental / Minnesota Department of Transportation, ownerBridge Description: Twin 1223-ft-long box girder bridgesReinforcement: Gerdau Ameristeel, West Allis, Wisc.Disk Bearings: R.J. Watson, Amherst, N.Y.Expansion Joints: D.S. Brown, Andover, Minn.Structural Components: 139 drilled shafts, four main pier footings, eight columns, and four-parallel box girdersfor the superstructures with precast segments for the main spans and cast-in-place construction for the side spansASPIRE, Fall 2008 | 29

psi were achieved. The last drilled shaftwas completed on January 12, 2008,(Day 89).Mass Concrete Footingsand PiersThe first mass concrete footing placementfor the main piers occurred onJanuary 15, 2008, (Day 92) and the finalfooting was completed on February 25,2008, (Day 133). Each rectangular footingsupports two 70-ft-tall concrete piers andtwo concrete box girders. The four mainpier footings vary in length from 34 ft to43 ft, in width from 81 ft to 112 ft, andin depth from 13 ft to 16 ft. The footingswere designed to span sections of theremaining unused foundation of the oldbridge, large drainage tunnels, and otherexisting utilities. These mass concretefooting placements were made withcareful control of curing temperaturesand thermal gradients using embeddedcooling pipes and a custom concrete mixdesign.The curved 70-ft-tall piers werecast beginning on January 23, 2008,(Day 100) with all piers of the bridgecast by March 14, 2008, (Day 151).Pier formwork was made for eachpier so that casting could take placeconcurrently. The sculpted pier shapehad been selected at the design charetteand is discussed in more detail in theWinter 2008 Issue of ASPIRE. Thesweeping curves of the piers weredeveloped to complement the paraboliccurves of the variable depth concretesuperstructure. In the longitudinaldirection, each pier has a 26-ft-widebase, curves in to an 8-ft width at midheight and then outward to 31 ft 8 in. atthe top. The concrete placement of thepier columns followed a similar processas the footings. The superstructure restson large disc bearings at the top of thepiers. Each main pier has three bearings;each bearing has a service load capacityof 5800 kips. The shape of the pierincludes concrete extensions to protectand conceal the bearings.Precast Segmentsfor the Main SpanThe main span superstructure segmentswere prefabricated using the long-linecasting method. Eight casting beds,each approximately 250-ft long, wereset up on the existing I-35W roadwayThe segments were lifted into place using a 600-ton, barge-mounted crane. Photo: Mn/DOT.on the south side of the project. The120 segments were precast and thentrucked and stored at the adjacent riverstaging area. Once the formwork wasremoved from the casting site, the newI-35W roadway was built with alignmentgeometry enhancements. The closeproximity of the precasting operationprovided good access to the river andcentralized, direct coordination betweenconstruction crews and the managementand engineering teams. Precastsegments vary in length from 13.5 ftto 16.5 ft, vary in depth from 25 ft atthe pier to 11 ft at midspan, and weighfrom 380 kips to 216 kips. As withthe piers, the use of multiple segmentbeds allowed segment production toproceed quickly; all eight beds were inproduction simultaneously. Concrete forthe first precast segment was placedon January 30, 2008, (Day 107). Rollingheated structures moved with thesegment casting to provide a reliablework and curing environment duringthe cold winter months. Concrete wasplaced even on the coldest day, February10, 2008, when the high temperaturewas -4º F and the low was -14º F, witha wind chill of -36º F. The final concretesegment was cast on June 6, 2008—128 days after precasting began.Concurrent Castingof Side SpansWhile the main span superstructuresegments were being precast, theadjacent side spans over land were beingcast-in-place on falsework. Using thesame box girder shape, the formworkwas installed. Then all reinforcingand longitudinal and transverse posttensioningwas placed. These spans werescheduled for an early spring concretecasting, which began on April 2, 2008,(Day 170) and was completed by theend of May. The entire bridge deck istransversely post-tensioned for addedriding surface durability.The power ofcreativity and innovation.30 | ASPIRE, Fall 2008

Main Span Erection—120 Concrete Segments in47 DaysAfter completion of the concrete sidespans, the starter precast segments ineach of the eight cantilevers wereerected. Precast segments weredelivered to the erection site by bargefrom the riverfront just downstreamfrom the nearby 10th Avenue Bridgeand lifted into place using a 600-ton,barge-mounted ringer crane. The firstsegment placed at the pier to begin theone-directional cantilever constructionbegan by using a 1-ft 6-in.-wide concreteclosure pour to optimize precisegeometric set-up. This was fine-tunedusing a series of jacks on a support frameattached to the pier cap. The match-castfaces of subsequent precast segmentswere coated with epoxy and then connectedto those previously erected usinglongitudinal post-tensioning. The firstprecast concrete segments were placedon May 25, 2008, (Day 223), while acrowd estimated at 800-1000 watchedclosely from the walkway of the adjacent10th Avenue Bridge. Each pair ofadjacent precast concrete segments wasconnected with a longitudinal cast-inplaceconcrete deck closure slab. Afterachieving a minimum compressivestrength of 4000 psi, the segment pairand the connecting longitudinal closurewere post-tensioned with a series oftransverse, top-slab deck tendons andlongitudinal, top-slab cantilever tendons.Segment erection operations continuedat all eight cantilever headings, withfour segments typically placed each day.The bridge’s last concrete segment waserected on July 10, 2008, (Day 269)taking only 47 days to erect the mainspan segments. A 7-ft-long long closurepour was made at midspan in each ofthe four cantilevers with final stressingof longitudinal post-tensioning tendonsto complete major bridge constructionoperations. From Notice-to-Proceed ofthe design-build contract to erectionof the final main span segment was 9months.A Smart Bridge with High-Tech Bridge MonitoringThe new bridge contains approximately323 sensors that will serve as a dataresource to verify the long-term serviceof the bridge and provide an importanttool for future bridge designs. Mn/DOT has formed a partnership with theUniversity of Minnesota Departmentof Civil Engineering and the FederalHighway Administration for use of theinformation from the sensors.Precast segments weighing up to 200 tonswere erected quickly. Photo: © FIGG.The 120 precast concrete segments to create the 504-ft-longmain span were erected in 47 days. Photo: © FIGG.A Modern Concrete Bridgefor the FutureI-35W is a modern concrete bridgedesigned for the future—a sustainable,redundant, high-strength, highperformanceconcrete bridge. This majorconcrete bridge will serve as an importantresource in the delivery of other majorbridges in the re-building of America’sinfrastructure. Ultimately, the success ofthis bridge is a reflection of remarkableteamwork of some 400 to 600 localskilled workers, the construction team,the design team, the subcontractorsand suppliers, Mn/DOT, FHWA, and thecommunity. Mn/DOT’s vision proved tobe achievable, demonstrating the powerof creativity and innovation._______________Linda Figg is president/chief executiveofficer of FIGG and served as I-35W visualquality manager. Alan R. Phipps is seniorvice president/director of operations ofFIGG and served as I-35W design manager.ASPIRE, Fall 2008 | 31

HPC Bridge ViewsIs Now Electronic OnlyStarting in 2008HPC Bridge Viewswill be distributedelectronically.To continue to receiveHPC Bridge Viewsyou must subscribeonline at:Newwww.hpcbridgeviews.orgDon’t miss any more issues.Subscribe today.U.S. Department of TransportationFederal Highway AdministrationTMconcretethe sustainablemedium of tomorrow’senvironmentArchitectural Concrete.The versatile building product for:• DURABILITY AND LONGEVITY• ENERGY EFFICIENCY• REFLECTIVE SURFACES• BETTER INDOOR AIR QUALITY• BEAUTIFUL & FUNCTIONAL STRUCTURESLEHIGH CEMENT COMPANYWHITE CEMENT DIVISION7660 Imperial WayAllentown, PA 18195-1040LehighCementis committedto sustainabledevelopment.Toll Free 1 800 523 5488Phone 610 366 4600Fax 610 366 4638www.lehighwhitecement.com32 | ASPIRE, Fall 2008

Experience, Innovation, Delivery … ValueBridges are complex components of our transportationinfrastructure. The planning, design, construction, and maintenanceof these important structures require experience, innovativeapproaches, and reliable project delivery—all aspects of Baker’svalue-based bridge services.Outstanding AestheticsUnique Delivery—Design Build; Accelerated Bridge ConstructionBridge Management—Inspection and Structural Health MonitoringBaker is seeking talented bridge engineers nationwideCreating value by deliveringinnovative and sustainable solutionsfor infrastructure and the environment.1.800.553.1153www.mbakercorp.com

BUYERS GUIDEThe companies listed on these pages have supported ASPIRE magazine during 2008. Each produces a high quality productor service targeted to the bridge industry and is worthy of yourconsideration. In choosing ASPIRE as the way to communicatewith you, they show enormous confidence in us.These companies shared in the significant success achievedby ASPIRE. Advertisers put their money where their mouthsare, and they can rightfully be proud of the expanded size ofthis issue and of our ambitious plans for 2009. They enableus to move ahead with confidence to better serve yourneeds.Just as important, the advertisers create valuable messagesfor our readers. Their announcements and productinformation supplement our own presentations to keepreaders current with new ideas.Whenever an opportunity arises, please contact an ASPIREadvertiser, ask them for more information, and thank themfor their investment in the bridge community. For an easyway to make a contact, go to www.aspirebridge.org andselect “Advertisers.” Clicking on any listing will take you totheir home page.We appreciate their support, and yours, for making ASPIREthe most read and talked about bridge magazine!Description Address/Phone WebADAPT-ABI is a simple, practical, and powerful softwarefor the design of segmentally constructed bridges -precast/CIP pre-/post-tensioned - including constructionsequencing and many other customized features.1733 Woodside Rd., Ste 220Redwood City, CA 94061650.306.2400www.adaptsoft.comErikssontechnologiesAVAR’s primary area of work is in the western US,including Alaska and Hawaii. For post tensioning ofprecast and cast-in-place, they work nationwide.Baker provides engineering and consulting services forclients worldwide and is consistently ranked in the top10% of design firms by Engineering News Record.The Admixture Systems business of BASF is a leadinginnovator in the development, manufacturing andmarketing of chemical admixtures for concrete.Bentley offers comprehensive bridge software solutionsfor design, analysis, and construction engineering: LEAPBridge and RM Bridge.Central Atlantic Bridge Associates. Promoting thebenefits, advantages, and performance of prestressedconcrete bridges in the Central Atlantic region.Campbell Scientific, Inc. – Manufacturer of dataacquisition systems for long-term, stand-alone monitoringof bridges and other structures: data loggers, software,sensors, telemetry, and power supplies.CH2M HILL provides transportation planning, designand construction services for some of the most complexhighway and bridge projects in the world.DYWIDAG-SYSTEMS INTERNATIONAL – Expertsin the design, manufacture, supply, and installationof THREADBAR ® , multistrand, and cable-stay posttensioningsystems.Eriksson Technologies is a bridge engineeringsoftware and technical services company, specializingin prestressed concrete design.504-F Vandell WayCampbell, CA 95008408.370.2100Airside Business Park100 Airside DriveMoon Township, PA 15108800.553.115323700 Chargrin Blvd.Cleveland, OH 44122800.628.9990685 Stockton DriveExton, PA 19341800.BENTLEY1042 North Thirty Eighth St.Allentown, PA 18104610.395.2338815 W 1800 NLogan, UT 84321435.753.23429191 S. Jamaica StreetEnglewood, CO 80112303.771.0900320 Marmon DriveBolingbrook, IL 60440630.739.1100P.O. Box 16396Temple Terrace, FL 33687866.Erikssonwww.avarconstruction.comwww.mbakercorp.comwww.masterbuilders.comwww.bentley.com/BrIMwww.caba-bridges.orgwww.campbellsci.comwww.ch2m.comwww.dywidag-systems.comwww.LRFD.comFIGG specializes exclusively in the design andconstruction engineering of American bridgelandmarks.800.358.3444 www.figgbridge.comFinley Engineering Group is an engineering andconstruction consulting firm specializing in complexbridge projects.Founded in 1947, Flatiron is one of the leadingproviders of transportation construction and civilengineering in North America. Its core competenciesinclude major bridge, highway, and rail projects.1589 Metropolitan Blvd.Tallahassee, FL 32308-3776850.894.160010090 E. I-25 Frontage Rd.Longmont, CO 80504303.485.4050www.finleyengineeringgroup.comwww.flatironcorp.com34 | ASPIRE, Fall 2008

Description Address/Phone WebGruppo De Eccher/DEAL provides engineering andspecial equipment for bridge construction.Via Buttrio,Frazione Cargnacco33050 Pozzuolo del Friuli(UD) - Italy+39 0432 607900www.deal.itHamilton Form produces custom steel forms andplant production equipment for the prestressed,precast concrete industry.Hatch Mott MacDonald specializes in technical advice,planning, design, program and construction management,and alternative project delivery for infrastructure clients.LARSA, Inc.’s software for bridge analysis and designaddresses specialized needs of a variety of bridgestructures, including cable, segmental, curved, box, andother types, and is a standard in leading U.S. firms.Lehigh Cement Company’s White Cement Divisionhas been the foremost producer of white cement inNorth America for over a century.PB is a leader in infrastructure development aroundthe world, dedicated to meeting the needs ofclients & communities.Since 1971, Scott System has been providingelastomeric form liners and brick-inlay systems forarchitectural concrete.SPLICE SLEEVE. The original grout-filled mechanicalsplice for rebar used for moment-resistingconnections in precast.Stalite is a high-performance lightweight aggregatewith a wide range of uses, including structurallightweight concrete.Standard Concrete Products, producer ofprestressed, precast concrete products has plants inTampa, Savannah, Atlanta, and Mobile.Sumiden Wire manufactures prestressing strandand epoxy coated prestressing strand, and distributesstressing hardware.ThyssenKrupp Safway, a full-service scaffoldingcompany, features the QuikDeck system for easyaccess under bridges.T.Y. Lin International is a full-service infrastructureconsulting firm recognized worldwide for its longspanand signature bridge design services, as well asseismic analysis and retrofit expertise.URS Corporation is one of the largest engineering,construction and technical services organizations,with approximately 50,000 employees in more than400 offices worldwide.VSL provides design support, construction systemsand services for precast segmental, cast-in-place andstay cable bridges.Williams Form Engineering Corporation has beenoffering ground anchors, concrete anchors, posttensioningsystems, and concrete forming hardwareto the construction industry for over 85 years.Zbar is a revolutionary new concrete reinforcingsteel (rebar) product that utilizes a patent pendingdual-coating process. This process involves thermalbonding to conventional reinforcing.7009 Midway RoadFort Worth, TX 76118817.590.2111127 Bleeker StreetMillburn, NJ 07041973.379.3400Melville Corporate Center105 Maxess Rd., Ste. 115NMelville, New York 11747800.LARSA.017660 Imperial WayAllentown, PA 18195800.523.5488One Penn PlazaNew York, NY 10119212.465.500010777 E. 45th Avenue,Denver, Colorado 80239303.373.2500192 Technology Drive, Ste. JIrvine, CA 92618-2409949.861.8393PO Box 1037Salisbury, NC 28145-1037800.898.3772PO Box 1360Columbus, GA 31902706.322.32741412 El Pinal DriveStockton, CA 95205209.466.8924202 Scotia GlenvilleIndustrial ParkScotia, NY 12302800.582.9391Two Harrison Street,Ste. 500San Francisco, CA 94105415.291.3700600 Montgomery Street,26th FloorSan Francisco, CA 94111415.774.27007455-T New Ridge Rd.Hanover, MO 21076888.489.26878165 Graphic Dr.Belmont, MI 49306616.866.0815Gerdau AmeristeelP.O. Box 1882Knoxville, TN 37901-1882888.637.9950www.hamiltonform.comwww.hatchmott.comwww.larsa4d.comwww.lehighwhitecement.comwww.pbworld.comwww.scottsystem.comwww.splicesleeve.comwww.stalite.comwww.standardconcrete.netwww.sumidenwire.comwww.safway.com/Products/QuikDeck.aspwww.tylin.comwww.thenewurs.comwww.vsl.netwww.williamsform.comwww.zbarusa.comASPIRE, Fall 2008 | 35

BOX BEAMSBEND BRIDGEby Jim Deschenes, Michael Baker Jr. Inc.After considering variousoptions, designers decidedon a five-span configurationwith integral bent caps tocreate a smooth, singlesuperstructure depth.All photos: MichaelBaker Jr. Inc.Concrete girdersoffer onlyalternative forfive-span bridgewith severehorseshoe bendAccess to a new upscale developmentin the foothills of Utah’s WasatchMountains just outside Salt Lake Cityrequired a grand welcoming entrance,along a path with difficult terrain. Tomeet the variety of needs producedby the site, especially environmentalconcerns and functional demands, tworeinforced concrete bridges located on“switchback” curves were built. Thelower bridge, discussed in this article,was an exceptionally challenging fivespan,450-ft-long bridge with a completeswitchback curve along a centerlineradius of only 80 ft and a 12% grade.Access to the site was limited bysteep grades, limits of a conservationeasement, and a requirement to providefor wildlife crossing. The project alsowas located less than 1000 ft fromthe Wasatch Fault. Typically, the mosteconomical solution would involvebuilding large walls and excavatingsteep slopes into the existing hillside.But foothill preservation and concernsfrom county officials, coupled with thedesire to create an aesthetically pleasingentrance, led the owner to investigatenonconventional alternatives.Once the concept for the switchbackcurves was devised, a series of designchallenges developed. The curve wastoo severe for tangent girders withoutreducing span lengths to less than30 ft, while curved steel girders werenot economical at such a small radius.Designers determined that the mostfeasible bridge type was a conventionallyreinforced, cast-in-place concrete, boxgirder bridge. The girders could notbe post-tensioned due to the severecurvature, which would have made itdifficult to resist the bursting forces inthe walls of the boxes.profile36 | ASPIRE, Fall 2008Big Cottonwood Canyon Loop Road Bridge / Salt Lake City, UtahEngineer: Michael Baker Jr. Inc., Midvale, UtahPrime Contractor: Ralph L. Wadsworth Construction Co., Draper, UtahConcrete Supplier: Harper Ready Mix, Salt Lake City, UtahAwards: 2008 Portland Cement Association Bridge Award

The most feasible bridge type was a conventionallyreinforced, cast-in-place concrete, box girder.Extensive evaluations led to a fivespanconfiguration with integral bentcaps that provided a smooth, singlesuperstructure depth. The superstructureitself consists of a three-cell box girderwith an overall depth of 5 ft 6 in.Due to the bridge’s severe curvature, thelength along the outside perimeter ofthe deck was considerably longer thanthe inside perimeter. This resulted inmore dead load on the curve’s exteriorside than on the inside. To minimizethe dead-load eccentricity, the columnssupporting the bridge’s curved portionwere offset from the centerline of thestructure. Fortunately, the offset wasminor relative to the superstructure’swidth and was not visible, so it did notaffect the design’s aesthetics.Reinforcement AddedChallengesReinforcement layout proved complicated.The curvature was enough torequire the No. 8 main longitudinalreinforcement to be bent at the bridgeradius. Smaller No. 5 bars were flexibleenough to be field bent and tied intoplace. Spacing of the transverse No. 5bars in the deck was determined bythe deck’s outside edge. Around thedeck’s curved portion, this required aradial placement of the bars. The resultwas a much closer spacing aroundthe curve’s inside edge. Epoxy-coatedreinforcement was used for the top slaband parapets, while the remainder ofthe reinforcement was uncoated.Multidisciplinary Center for EarthquakeEngineering Research guideline. Aresponse spectra analysis was performedto determine the seismic design forces,and specific elements were designed forthe maximum overstrength properties ofthe columns.Two concentric reinforcement cageswere used in the columns to achievethree goals: maintain an aestheticallypleasing 7-ft-diameter column size,provide the seismic design strengthrequired in the column, and limit thecolumn strength for which the footingshad to be designed. Only the innercage extended into the bent cap andfooting. The outer cage was essentiallytemperature reinforcement although itseffects on column strength were takeninto consideration for seismic analysisPost-tensioning the girders was not anoption due to the severe curvature,which would have risked damage to thebox girder walls.of the structure and for determiningthe design strength for the capacityprotected foundation and bent capelements.Several analytical models were createdto determine the best seismic designfor the bridge, which is located alongthe largest and most active fault line inUtah. A site-specific analysis showed apeak ground acceleration of 176% ofgravity. The final solution used SeismicDesign & Analysis Procedure D from theThe dramatic switchback curve achieved for the entrance to a new housing developmentin the foothills of Utah’s Wasatch Mountains near Salt Lake City minimized the impacton the environment, but created tremendous challenges to design and construct.450-ft-long reinforced concrete box girder bridge / Wasatch Pacific LLC, OwnerBridge Description: Conventionally reinforced, five-span, three-cell, concrete box girder bridge designed for steep grade and centerline radius of80 ft, as well as high seismic forcesBridge Construction Cost: $170/ft 2 (bridge only)ASPIRE, Fall 2008 | 37

the superstructure so stiff that there is asignificant load transfer through the boxsection to all of the foundations.As the bridge climbed the steep hillside, adjustments were made to make the footingsdeeper and create a more balanced distribution of seismic forces between the columns.Reinforced concrete offered the only optionfor reaching all the desired goals.Aesthetic Goals ExpandInitial budget restraints limitedarchitectural concepts to staining theconcrete and adding some fracturedfinrelief in the parapet. As the designdeveloped, the owner realized theopportunity to create a showcaseentrance to the development, andthe budget was expanded to includearchitectural enhancements. Theadditions were made too late to includesome early suggestions proposed onthe owner’s renderings, such as treeplanters, variable-depth barriersthat extended below the deck, orasymmetrical trapezoidal piers.The design was modified to providea more modern-looking parapet thatincluded an LED lighting strip placedunder an overhang in the parapet’sA Sustainable SolutionPreserving the natural habitat around this bridge, especially for deer and small-animalcrossings, and minimizing impact to vegetation on the hillsides, were key goals in designingthe structure. The county also required a public trail that could be maintained through theproperty. All agreed that creating a bridge was an aesthetic improvement over the otheroption—a large hillside cut.The cast-in-place concrete optionprovided flexibility for the tight radiusand steep grades, but it also fits well withthe rocky surroundings.As the bridge climbed the steep hillside,adjustments were made to make thefootings deeper and create a morebalanced distribution of seismic forcesbetween the columns. Substantialcheekwalls and finwalls at the abutmentsengaged soil passive pressure in thetransverse direction. The columns andbent footings were required to resistlongitudinal seismic forces, as theabutments were parallel to each otherand could only resist seismic forces inone direction.Ultimately, because each span wasrelatively short, at about 90 ft, theseismic forces that the columns weredesigned to meet were not unusual. Thestructure acts much like a table, withChoosing the cast-in-place concrete option was driven by its flexibility in creating thestructure’s tight radius and steep grades, but it also fits well with the rocky surroundings. Thefinished structure was stained to complement the colors of the canyon.Concrete also used Utah’s abundant natural-aggregate sources. Steel would have had to beshipped from mills and then fabricated and transported to the site, whereas aggregate wasreadily available within a few miles of the site. The narrow space constraints also played toconcrete’s strengths, as steel girders would have required a large crane pad and pull-throughareas for trucks. Concrete allowed the contractor to minimize site impacts by having onesmall crane to handle formwork, and the same pad was large enough to accommodate theconcrete pump and trucks.A critical constraint was a conservation easement located just outside the roadway’sproposed edge. Spread footings were found to work well with the available soil pressure,while shoring kept the spread-footing excavations from encroaching into the easement.Caissons would have minimized the hillside cut and remained clear of the easement butwould have cost more than spread footings.LED lighting was placed under a lip at the parapet’s interior, delineating the parapet’s edgeto drivers without casting light upward or outward to detract from the canyon’s darkness.This approach alleviated light pollution and enhanced the natural environment.The concrete design allowed the bridge to not only meet all of the owner’s functional andaesthetic needs but provided a minimal impact on the natural environment, blending it withits surroundings successfully.38 | ASPIRE, Fall 2008

The owner realized the opportunity to createa showcase entrance.face. Two 3-in.-diameter conduits wereprovided in the barrier to carry powerand fiber optics to the LED lights, withcustom light boxes embedded in theparapet.Formwork and ConcreteDesign and analysis did not stopwhen the design plans were released,as designers also had input into theshoring design and concrete placementsequence. Numerous site visits weremade and a number of geometry checkswere performed at the request of thebuilder, with minor detail changes madeto facilitate forming.The bridge’s location allowed thesuperstructure’s concrete slabs and wallsto be cast on continuously supportedformwork. Hundreds of conventionalscaffold shoring towers supporteda plywood deck and wall forms. Thescaffolding was left in place until thetop deck was cast. Parapets were placedafter shoring was removed.Bottom slab and wall forming requiredan enormous amount of surveying tocreate the correct curvature and slope.The goal was to generate smooth linesand not rely on short tangent sectionsto produce the curve. The web wallswere short enough to allow 1/2-in.-thick plywood to be used, and it waswarped around the curve. The deck wasparticularly difficult to form and place,as no two interior box cells had theThe bridge’s initial budget was expandedwhen the developer realized he couldmake a strong statement for the entry tothe residential development.same dimensions. The deck was formedby painstakingly custom-cutting 2x6timbers and plywood.Placement of the deck concrete provedto be one of the more challengingaspects. The horizontal curve, superelevation,and difference in lengthbetween the deck’s interior and exteriorwalls produced a warped surface.A simple roller screed was used, andthe deck was placed in four separatesections.Despite the 12% centerline grade,the deck was placed with the screedtraveling downhill. The contractor’sexperience building the Olympic bobsledtrack and ski-jump landing hill alleviatedfears that are typically associatedwith placing concrete downhill. Therelatively light roller screed had to bepulled downhill to screed the concrete.The contractor maintained a head ofconcrete in front of the screed, andno evidence of poor consolidation ordownhill slumping occurred.As a final measure of protection, a 3/8-in. thick modified polymer overlay wasplaced on the deck approximately 1 yearafter the final deck placement.Designing and constructing this projectwere challenging, yet the designersremain convinced that reinforcedconcrete offered the only option forreaching all the desired goals. The useof many computer models and handcalculations was essential, as the uniquegeometry pushed the engineeringwell beyond the scope and codes ofconventional bridge design. Closeinteraction between the designer andbuilder was critical in constructing thebridge within the owner’s scheduleand achieving a design that providesan impressive gateway into thedevelopment._______________________Jim Deschenes, is an engineer, officeprincipal, and assistant vice president withMichael Baker Jr. Inc. in Midvale, Utah.For more information on this or otherprojects, visit www.aspirebridge.org.AESTHETICSCOMMENTARYby Frederick GottemoellerContext-sensitive design has becomethe goal for much bridge design. TheBig Cottonwood Canyon Loop RoadBridge is as fine an example of contextsensitivedesign as one is likely to see.Tucked into a fold in the landscape,with its single, almost centrally locatedcolumns hidden in the shadows, thebridge seems to float over the ground,looking like it has always been there.The cast-in-place concrete box girder,with all of the connections and pointsof force transfer hidden inside the box,shows only a smooth continuous surfacefollowing the geometry of the roadway.The torsional stiffness of the concretebox girder form allows for all of the difficultforces resulting from the extremegeometry, loads, and seismic effects tobe handled gracefully. All of the detailssupport the overall form. The parallelshadow lines of the parapet emphasizethe geometry, while the color well suitsthe location.The renowned twentieth centuryarchitect Mies van der Rohe famouslysaid, “Less is More,” meaning thatadding more detail often detractsfrom, rather than adds to, a design. Itis fortunate that time did not allow theaddition of the “asymmetric trapezoidalpiers” and “variable depth barriers”to this structure. They would not andcould not have improved its appearance.The unusual geometry of the bridge hasbrought out the best in the designers.Best of all, it means that users can enjoythe appearance of the bridge even whilecrossing it.ASPIRE, Fall 2008 | 39

New construction systemprotects environmentallysensitive areasTechnology Drivenby Craig A. ShuttConstructing the new WashingtonBypass, an upgraded alternative routefor U.S. Route 17 in Beaufort County,N.C., created unique challenges beyondtraditional bypass construction. The$192-million project, encompassing6.8 miles of roads, includes two majorinterchanges and bridges that spanenvironmentally sensitive lands. To meetthe variety of needs, especially the goalof minimizing impact to wetlands, theconstruction team created an innovativegantry system that drives piles, setsprecast bents, and erects beams. Afterthe deck is cast, the gantry progressesto the next span.The bridge construction represents thesecond part of a three-part project,explains Maria Rogerson, assistantresident engineer with the NorthCarolina Department of Transportation(NCDOT). The first part, begun inFebruary 2008, focused on wideningprofileU.S. Route 17 Washington Bypass / Beaufort County, N.CDESIGN-BUILDER: Flatiron/United, a joint-venture company comprising Flatiron Construction Corp., Longmont, Colo.,and United Contractors Inc., Chester, S.C.ENGINEER OF RECORD: Earth Tech Inc., Long Beach, Calif.PRECASTER: Coastal Precast Systems, Chesapeake, Va., a PCI-certified producerGANTRY: Deal, Italy40 | ASPIRE, Fall 2008

The innovative gantry system used onthe U.S. Route 17 Washington BypassBridge in Beaufort County, N.C., drivespiles, sets precast concrete bents, anderects beams. After the deck is cast,it progresses to the next span.All photos: Flatiron.Design-Build OpensOpportunity“What gave us the ability to be a littlebit creative on this project was thedesign-build process,” says Rogerson.The state has created several smallerdesign-build projects prior to this one,she notes, but the delivery method hasnot been used extensively. Bidders werescored both on their creativity in meetingthe variety of needs, as well as the costto deliver the bridge. Three companieswere short-listed based on their bidsand technical proposals. Initially, all threebids came in too high, so adaptationswere made to make the design morecost efficient. It is the largest designbuildproject in the state.“The design-build process cuts thetimeframe on construction before theNCDOT acquires the bridge, because thecontractor is responsible for final design,right-of-way access, and construction intheir contract,” Rogerson explains.The Flatiron competitively priced proposalwas accepted because, among otherfeatures, it did not require the use of atemporary work bridge to erect thestructure, which would have had moreimpact on the wetlands, she notes. “Theirdesign required less clearance in thewetland areas, only 30 ft from the edge ofthe bridge, with minimal impact below.”Executing this concept then became thedesign-build team’s responsibility.Innovative Gantry SystemThe bridge is being constructed usingtwo 592-ft-long, patent-pending gantrysystems starting from each end of thebridge. Each gantry consists of twoparallel and connected trusses that arelong enough to reach over four spansof the bridge. The gantry system beginsat one end of the bridge and drivesthe piles for each bent. Approximately1227 30-in.-square. precast, prestressedconcrete hollow piles will be drivento support 140 spans including bothportions of the Y-shaped split at theend. Each span is about 121 ft long.Earlier, test piles had been driven nearthe bridge’s alignment to confirm thelength of the piles and tip elevations.The precast concrete piles and girderswere fabricated off site while the pilecaps were cast on site at a precastingyard set up at the south end of thebridge. The components are inspectedand approved at both sites prior todelivery to the gantry.Gantry OperationThe precast piles and beams aredelivered to staging areas at the northand south abutments and then loadedonto a special carrier that comprisestwo trucks, one driving forwards andone driving backwards, explains Elie H.Homsi, vice president of engineeringservices at Flatiron Constructors Inc. anddeveloper of this top-down concept.the southern 4 miles of two-laneroadway to four lanes. Construction ofthe new 2.8-mile-long bridge, spanningwetlands along the 6.8-mile-longsection of roadway, is now underway.It will be followed by widening 4 milesof highway north of the bridge undera contract to be let toward the end of2009. The goal is to create an accessible70-mph corridor from Virginia down toWilmington, N.C., she explains.The pile is loaded into the lead with an attachment forthe hammer clamped to its top. The lead then rotatesthe pile into a vertical position for driving.precast, prestressed concrete bridge / North Carolina Department of Transportation, OWNERBRIDGE DESCRIPTION: Precast concrete bridge consisting of 140 spans (116 spans plus two parallel structures of 12 spans) each about 121 ft long,with 1227 precast, prestressed concrete hollow piles, 922 precast beams, 140 precast post-tensioned pile cap bents and cast-in-place concrete deckPILE DRIVING EQUIPMENT: Birminghammer, Hamilton, Ont., CanadaBRIDGE CONSTRUCTION COST: $192 millionASPIRE, Fall 2008 | 41

The gantry system is used to attach pile caps in three pieces to the precast concrete piles.The trucks position the pile under thetail of the gantry, where two separatetrolleys lift each end. The pile is threadedinto the lead and an attachment for thehammer is clamped to the top of thepile. The trolleys move to the end of thegantry, and the lead rotates the pile intoa vertical position for driving.The entire gantry is mounted onfront and rear supports. Each supportcan move independently forwards,backwards, and sideways. The frontsupport can be moved to the right whilethe back can be moved to the left, toskew the positioning, or they can bemoved in the same direction to keepcomponents parallel, Homsi explains.The sideways movement allows thegantry to be positioned to reach thelocations of the piles and the beams.On typical spans, the gantry drives ninepiles and then sets the precast concretecaps in three pieces on the piles. The capsEnvironmental ChallengeThe challenges were significant forthe design team. The key element wasbuilding the 2.8-mile-long bridge oversensitive wetlands that could not bedisturbed and opening it to traffic byNovember 2010, bringing it in linewith the widening projects planned tothe north and south. Complicating thisprocess was a moratorium by the stateWildlife Resource Commission for no “inwater” pile-driving work from February 15to June 15 to allow for fishery hatching ofthree species.are post-tensioned and infill concrete isplaced. The concrete infill is loaded intobuckets and transported to the leadingend of the truss using the gantry trolley.The trolley maneuvers the bucket into theposition required for concrete placement.Next, seven beams are placed by thegantry and the concrete deck is cast.Once the 3500-psi concrete compressivestrength is achieved, the gantry movesforward, and the cycle is repeated forthe next span.“This new method allowed the Flatiron/United team to break the record fortop-down construction for this type ofprecast beam bridge by constructing120-ft-long spans without relying onground-based support equipment,” saysHomsi. The truss eliminated the need toerect a temporary bridge and significantlyreduced the environmental impact. Fewertrees has to be cut down using thismethod.The innovative top-down constructionmethod results in minimal disturbanceto the wetlands during the constructionoperation. The only permanent impact isthe actual pile footprint.On typical spans, the gantry drivesnine piles, then sets the precastconcrete caps in three pieces onthe piles. The caps are then posttensionedand infill concrete placed.Mark Mallett, project manager for theFlatiron/United joint venture, explains,“The gantries are essentially a bridgebuildingassembly line. There are threespans of bridge under constructionin the launching cycle at all times. Itis one challenge to get the gantry toperform each of its tasks and another tosynchronize these tasks so that all threespans can be built simultaneously.”The gantry progresses in a “caterpillar”mode of movement, Homsi says,stretching out the front support to itsnew location and retracting the rearsupport as construction progresses. Thegantry is driving piles for the leadingor first span as the deck is cast on thesecond span and the deck concrete iscuring in the third span.Achieving the needed concrete strengthat the rear of each segment was thekey to being able to progress, Rogersonnotes. About four spans could be set eachmonth. “It moved along pretty well.”All of the construction is movingsmoothly, she adds. There are penaltiesof $10,000 per day for late completion,but no one is worried at this point. “Sofar, we’re remaining on schedule,” shesays. Meeting that schedule with such aninnovative approach to the constructionwill no doubt gain the attention of otherdepartments of transportation, as morestates look for ways to complete projectsquickly while minimizing the impact totheir sensitive environmental areas.42 | ASPIRE, Fall 2008

With energy, sustainability, safety, fire resistance, andprice escalation all dominating today’s headlines, it isclear that the world of bridge design is changing dramatically.Designers now have to consider many more factorsin their bridge solutions than in the past. Post-tensioning(PT) can be a valuable tool in addressing these concernsand has some unique advantages.The inherent efficiency of post-tensioned concretecan yield lighter and more durable structures. PT bridgesuse less concrete and steel reducing energy use and CO 2emissions. With sharply escalating material costs, thesesavings translate into improved economy.Post-tensioning has played a vital role in facilitatingsegmental bridge construction. It is also being used inmany innovative ways to improve bridge performanceincluding specialized applications such as cable-stayedand extradosed bridges and spliced concrete girders toextend span capabilities. PT bridge decks are being usedto reduce superstructure weight, increase girder spacing,and improve deck durability through improved crackcontrol. And the list of uses is growing. For example,PT bridge approaches have shown promise in solvingthe age-old maintenance problems associated withapproach slabs.Want to know more about post-tensioning? ContactPTI or visit our website at www.post-tensioning.org. Forhands-on instruction, plan to attend one of PTI’s BondedPost-Tensioning Certification workshops. The nextcourse will be held in Austin, Tex., October 27-29, 2008.049_DSI_ADUS_178x117 20.12.2006 11:06 Uhr Seite 1DYWIDAGPost-Tensioning Systems Multistrand Post-Tensioning Systems Bar Post-Tensioning Systems DYNA Bond ® Stay Cable Systems DYNA Grip ® Stay Cable Systems Engineering Construction Methods Stay Cable Testing Supply and InstallationDYWIDAG-SYSTEMS INTERNATIONALHQ America Business Unit 525 Wanaque Avenue 4732 Stone Drive, Suite BPost-Tensioning & Reinforcement Pompton Lakes, NJ 07042, USA Tucker, GA 30084, USADYWIDAG-SYSTEMS Phone (973) 831-6560 Phone (770) 491-3790INTERNATIONAL USA INC.320 Marmon Drive320 Marmon Drive Bolingbrook, IL 60440, USA 1801 N. Peyco Drive 2154 South StreetBolingbrook, IL 60440, USA Phone (630) 739-1100 Arlington, TX 76001-6704, USA Long Beach, CA 90805, USAPhone (630) 739-1100 Phone (817) 465-3333 Phone (562) 531-6161Fax (630) 972-9604E-mail: dsiamerica@dsiamerica.com www.dsiamerica.comASPIRE, Fall 2008 | 43

Repeating Historyby Christopher D. Baker, VHB-Vanasse Hangen Brustlin Inc.One of America’searliest open-spandrelarch bridges isreplaced whilemaintaining thebridge’s originalappearanceThe original Lime Kiln Bridge was theonly open-spandrel, concrete archbridge in Vermont and one of the firstbuilt in the United States. Since 1913,it stood as an architectural and scenicgem, spanning the majestic WinooskiRiver Gorge. Ordinarily, replacing a300-ft-long bridge would not requirean elaborate design—but the LimeKiln Bridge clearly was not ordinary.Constructing the new structure involveda challenging design, a challenging site,and a challenging process.Officials at the Vermont Agency ofTransportation (VTrans) sought toupdate the irreparably deterioratedstructure with an efficient crossing whilepreserving the original’s architecturaland historic integrity. And, of course,the work had to be done in as short ofa time frame as possible using the mostcost-effective techniques.The original bridge built in 1913was substantially rehabilitatedin 1940 shown here and 1991.The bridge connects South Burlingtonand Colchester by spanning a100-ft-deep gorge cut by the WinooskiRiver. The original design featuredreinforced concrete arches and teebeams, which were substantiallyrehabilitated in 1940 and 1991. Torecreate that look while meeting thevariety of contemporary needs, VTransand VHB held numerous meetings overa 3-year period to consider constructionoptions and receive input from allstakeholders, including the VermontDivision for Historic Preservation.Aerial Photography:Fli-Rite Aviation,Burlington, Vt.profileLime Kiln Bridge / Winooski River Gorge, Vt.Engineer: VHB-Vanasse Hangen Brustlin Inc., Bedford, N.H.Geotechnical Engineer: Golder Associates, Manchester, N.H.Prime Contractor: Kubricky Construction Co., Glen Falls, N.Y.Precaster: J.P. Carrara & Sons, Middlebury, Vt., a PCI-certified producer44 | ASPIRE, Fall 2008

Ultimately, the decision was made tocreate a structure combining precast,prestressed concrete box beams andslabs with cast-in-place concretearches. This combination replicated theoriginal bridge’s decorative geometricalfeatures and ornamental railings whileallowing sidewalks and travel waysto be widened. Street lighting andarchitecturally treated abutments andretaining walls also were added.Many Options ConsideredA number of alternatives wereconsidered before the final selectionwas made. The considerations includedrehabilitation possibilities, but it wasultimately decided that they wouldprovide no more than 20 years ofservice life, and more was desired. Aconventional steel-girder replacementbridge also was deemed incompatiblewith the goal of maintaining the senseof aesthetics, history, and pride of placethat the original bridge created.As a result, VHB and VTrans developedseveral concrete arch bridge concepts.Finding the best option requiredmeeting specific geometric criteria, andthe review process for each submissionphase was much more intense than fora typical project. Fortunately, completelyfilling one of the two quarries thatsqueezed the site’s perimeter allowedimproved alignment options duringthe conceptual stages. These changesprovided the opportunity to improve theproject and avoid significant impacts tothe local environment.The bridge’s ultimate geometry balanceda number of factors, including reducingcosts, simplifying geotechnical solutions,minimizing the number of joint locations,and maximizing the service life.The placement of the south abutmentwas dictated by a utility bridge, locatedupstream from the existing arch bridge,and by the depth of the fill overlyingthe bedrock, which sloped steeplydown to the gorge. Soils in this areawere unsuitable for spread-footingfoundations, so a stub abutmenton steel H-piles was selected. Thisconfiguration minimized the footprintof the abutment and eliminated theneed for deep excavation adjacent tothe water.The north abutment’s placement wasdetermined by several restrictions,The new Lime Kiln Bridgereplicates the look of theoriginal bridge, whichwas one of the first openspandrel,concrete archbridges in the United Statesand the first in Vermont.Concrete Arch / Colchester and South Burlington, Vt., OwnersBridge Description: Open-spandrel arch crossing a 100-ft-deep gorge using 80 precast, prestressed concrete beamsand cast-in-place arches, piers, floor beams, and deckConcrete Supplier: S.T. Griswold, South Burlington, Vt.Bridge Construction Cost: $6 millionASPIRE, Fall 2008 | 45

depth of the beams provided the requiredvertical clearance over the railroad, whiletheir appearance from underneath thestructure is more uniform, contributing toits aesthetic appeal.The 300-ft-long bridge features precast, prestressed concrete box beams and slabswith cast-in-place concrete arches, piers, floor beams, and deck. The arch supports sixintermediate 22-ft-long spans that used 1-ft-deep precast concrete solid slabs.comprising a railroad track to thenorth and limited horizontal clearancesfrom the centerline of the track to theabutment’s face. The abutment wasplaced to allow excavation for theabutment footing without requiringtemporary support of the railroad track.Other restrictions included a minimum23 ft vertical clearance, span-lengthlimitations, and the varying fill over thebedrock. The abutment was founded ona mechanically stabilized earth backfillbecause of its suitability to the height,soil conditions, and cost.Arches Resemble PolygonsThe two arches were designed withreinforced, cast-in-place concreteto closely match the shape of anequilibrium polygon under full deadload. The arch spring line was placedat equal elevations for each archfoundation. The clear distance betweenthe arch footings was about 121 ft withthe bottom of the arch rising to about28 ft above the spring line. In section,each arch is 4.5 ft wide and varies indepth from 4 ft at the spring line to3.25 ft at the arch’s midspan.Footings for the arches were designedto be about 12 ft wide and 22 ft longto accommodate the proposed arch andpier geometry, as well as the designloads. Information from soil boringsand geological survey helped set thebottom elevations for both foundations,ensuring they were seated in bedrockfor at least half of the footing’s heightat the back. This placement ensuredRemote-controlled, steerable dollieswere used to maneuver the 104-ft-longprecast concrete box beams. Photo: J.P.Carrara & Sonssufficient resistance against the archthrust and overturning moments.Precast Extends Design LifeThe arches support six 22-ft-longintermediate spans consisting of1-ft-deep precast, prestressed concretesolid slabs that were transversely posttensionedafter placement. Precastconcrete units were used rather thancast-in-place options to minimizeformwork over the gorge and increasethe deck service life. The slabs aresupported by elastomeric bearings oncast-in-place floorbeams at the spandrelarch columns and pier columns.The end spans of 59 ft and 103 ft useprecast, prestressed concrete adjacentbox beams that were transversely posttensionedafter placement. The boxbeams provided a number of benefits,including reducing costs through the useof repetitive construction for the bearings,beams, concrete overlay, and joints forlive-load continuity. The relatively shallowThe precast concrete beams also willsimplify construction phasing for futuredeck rehabilitation, since traffic phasingcould be easily accommodated dueto the continuous support providedby the underlying transversely posttensionedbeams. The box beams aresupported on elastomeric bearings.Bearing connections were detailed sothat the superstructure was fixed ateach pier bent column with expansionaccommodated at each abutment.AestheticsDesigners paid particular attentionto aesthetics in shaping the bridge’sprofile. The arch was symmetrical, withconcrete columns for the intermediatespans transmitting superstructureloads vertically to the arch. Aestheticconsiderations included the visual depthof the approach spans, the depth ofthe intermediate spans, and the postspacing for the concrete bridge railings.To aid the bridge’s appearance,approach-span depths on each endwere maintained at 3.5 ft, althoughthe depths for the south approachcould have been reduced to 2.25 ft.Designers decided that a uniform lookprovided better aesthetics and cut costsby allowing repetitive fabrication anderection procedures for both spans. Theminor premium for the deeper beamswas more than offset by the savings inThe end spans feature precast,prestressed concrete butted boxbeams that were transversely posttensionedafter placement.46 | ASPIRE, Fall 2008

Street lighting and architecturallytreated abutments and retainingwalls also were added, as wellas historical background on theoriginal bridge.Advertisers IndexAdapt. ....................... 59Baker ........................ 33BASF......................... 19Bentley/LEAP ..... Inside Front CoverCampbell Scientific............. 57DSI. ......................... 43Eriksson Technologies.......Back CoverFlatiron....................... 27FIGG ...........................3Gerdau Ameristeel.............. 47Hamilton Form..................51Lehigh Cement................. 32PB .......................... 15PCAP—CABA.......Inside Back CoverPCI. ......................... 62Splice Sleeve. ................. 52Stalite........................ 23Sumiden Wire. ................ 53T.Y. Lin International ............ 14ThysennKrupp. ................ 59URS............................7VSL ............................4Larsa ..........................5Williams Form Eng. Corp. ........ 63ZBar ad_ASP_JUN08_half pg vert3:Aspire 5/28/08 9:03 AM Page 1efficiencies and the fewer prestressingstrands required in the shorter span.For the intermediate spans over thearches, the floor beams were taperedto match the approach-span box-beamdepths at the fascia. Visually, this helpedtie together the intermediate andapproach-span superstructure.The cast-in-place concrete deck had aminimum thickness of 5 in., with a heatappliedwaterproofing membrane and 3in. of bituminous concrete. Texas classictraffic railing type T411 with decorativelighting attached was installed forsecurity and to add to the bridge’saesthetics. The railing posts over thefloorbeams and columns provided visualcontinuity between the superstructureand the supporting-arch structure andsubstructures.The completed bridge spans the majesticWinooski River Gorge just as elegantlyas did its venerable predecessor. Mostimportant, all parties to this long,complex, process-heavy project werepleased with the result. Innovation,collaboration, patience, persistence,and constant advancement in the stateof-the-artuse of concrete materials,combined with pure will on the partof the entire construction team, madethis bridge possible. Contemporarymaterials blended with a respect forthe past helped preserve the bridge’sarchitectural and historic integrity.____________Christopher D. Baker is principal/nationaldirector—structural engineering at VHB-Vanasse Hangen Brustlin Inc. in Bedford, N.H.REINFORCING STEEL BAR... Steel scrap is the primary raw material usedin the production of Gerdau Ameristeel reinforcing steel. Our mills re-usemore than nine million metric tons of steel each year, makingGerdau Ameristeel the Second Largest Recycler inthe Americas.THERMALLYAPPLIED ZINCINNER COATING...Durable; providingcathodic protection forthe steel as needed.ELECTROSTATICALLYAPPLIED POWDER OUTERCOATING... ZBAR’s first lineof defense against water andchlorides which lead to corrosion.CALL 888-637-9950FOR SALES & ORDERING INFORMATIONwww.gerdauameristeel.com/zbarHIGH PERFORMANCECORROSION PROTECTIONASTM A1055 COMPLIANTStandard Specification for Zinc and EpoxyDual Coated Steel Reinforcing Bars.MEETS FHWA HIGHWAY FOR L.I.F.E. REQUIREMENTSASPIRE, Fall 2008 | 47

The double-tee beamswere post-tensioned overa length of 980 ft.The Russian River Bridge uses nonstandarddouble-tee beams. Photos:Steve Hellon and John Huseby, Caltrans.EMERGENCYREPLACEMENTOF THERUSSIAN RIVER BRIDGEBy Ahmed M. M. Ibrahim, Linan Wang, Tariq Masroor, Minh Ha,and Ofelia Alcantara, California Department of TransportationDimensions of the non-standarddouble-tee beam. Drawing:Ahmed M. M. Ibrahim.The existing steel truss bridge, built in1932, over the Russian River in Geyserville,Sonoma County, Calif., was severelydamaged during a series of storms inthe last two weeks of December 2005.A maintenance crew from the CaliforniaDepartment of Transportation (Caltrans)observed lateral rotation of a mid-channelpier and approximately 8 in. of differentialsettlement between the upstream anddownstream sides. The bridge was closed totraffic on January 1, 2006, causing hardshipto the local community. It is the shortestroute to the high school on the other sideof town and closure of the bridge resultedin a 40-minute detour every school day.Caltrans studied the options of repairingor replacing the bridge. After sitegeology and scour mitigation studieswere completed, Caltrans decidedto replace and re-open the bridge totraffic before the next school year. Thereplacement bridge layout was to havethe same overall length, profile, andvertical clearance over the channelas the existing bridge. Matching theexisting layout was made mainly tominimize the time in acquiring right ofway and to keep the number of permitsto a minimum. Raising the bridge profileand consequently extending the bridgelength would have led to legal issues.profileRussian River Bridge / Geyserville, SONOMA COUNTY, Calif.Engineer: California Department of Transportation, Sacramento, Calif.Prime Contractor: CC Meyers Inc., Rancho Cordova, Calif.Contractor’s Consultant: R.N. Valentine Inc., Gualala, Calif.Precaster: Con-Fab California Corporation, Lathrop, Calif., a PCI-certified producerAwards: ASCE, Bridge Project of the Year, Region 9 (California), 2007; Associated GeneralContractors, Excellence in Partnership Award, San Francisco Chapter, 200748 | ASPIRE, Fall 2008

Sensitive environment and tight constructionwindow led to a precast alternative.Contract PlansCaltrans’ engineers started the designduring the first week of February 2006.The replacement bridge was designed tocarry two 12-ft-wide traffic lanes; 8-ft-wideshoulders at each side; and a 5.3-ft-widesidewalk for an overall width of 49.15 ft.Overall length of the replacement bridgewas 980 ft. Hydraulic considerationsrequired the use of fewer spans for thereplacement bridge. Eight 102.5-ft-longspans and two 80-ft-long spans at theends were used. To provide free boardclearance for the 100-year design flood,the superstructure depth was limited to 45in. with a span-to-depth ratio of 27 for thelonger spans.Due to sensitive environmental issuesand regulations, the limited constructionwindow was from May to the end ofAugust, and falsework was not allowedin the main channel. These restrictionsled to the use of a precast, prestressedconcrete bridge as the most suitablealternative. Four standard sections wereexamined during type selection: I-beams;bulb-tee beams; spread box beams; andadjacent box beams. All four alternativesused simple span beams made continuouswith a cast-in-place composite deck. EveryA two-column drop bent cap withaesthetic features was used to supportthe superstructure.effort was made to produce a design thatused state standard sections and was a faircompetition for all precast manufacturers.Standard I- and bulb-tee sections did notwork due to limited superstructure depthand required the use of non-standardsections. Spread box beams requiredusing less than 2 ft distance between thegirders and the use of formwork for deckplacement in such a short distance. Thissection was deemed impractical and wasruled out. Adjacent box beams were theonly standard section that met the highspan-to-depth ratio. Standard precast,prestressed AASHTO box beams 48 in.wide and 39 in. deep, with a 6-in.-thick,cast-in-place reinforced concrete deck wereselected. The adjacent beams were to betransversely post-tensioned at the quarterpoints. A total of 120 beams would berequired.hydraulic suitability and were preferredover cast-in-drilled hole (CIDH) pile shaftsbecause of the potential for a cave induring drilling.A few aesthetic measures were consideredfor the bridge bent caps, beams, andbarriers. The bent caps were designedwith simulated capitals, rounded nosesand arched soffits to visually reduce theirotherwise massive appearance. This effortaided in bringing the bent caps and columnshafts into a closer proportional relationshipto each other. The smooth vertical face ofthe precast box beams contributed to thetidy effect of the superstructure exterior,thus complementing the nautical themeof the barriers’ surface treatment andcontext-sensitive handrails.By mid March, the design package ofplans, specifications, and cost estimateswas ready for bidding. Bids were based notonly on the cost for the work to be done,but also on the product of the number ofLifting the double-tee beams at theprecasting yard.The precast box beams were to besupported on cast-in-place drop bent capsusing two elastomeric bearing pads ateach end of each beam. The drop bentcaps would have a constant width of 6ft and a variable depth with minimumdimension of 6 ft. Each drop bent cap wasto be supported by two cast-in-steel shell(CISS) pile shafts. Cast-in-steel shell pileshafts were chosen based on their highload-bearing capacity, site conditions, andSequence of construction stages.Drawing: Ahmed M. M. Ibrahim.Continuous post-tensioned, double-tee beam / California Department of Transportation,Sacramento, Calif., OwnerPost-Tensioning Supplier: AVAR Construction Systems Inc., Campbell, Calif.Bridge Description: Precast, prestressed concrete non-standard double-tee beams made continuous using a 6-in.-thick cast-in-place compositedeck and two-stage post-tensioning. Eight spans 102.5-ft long and two end spans 80-ft long for a total length of 980 ftStructural Components: 60 precast girders, 24 cast-in-steel shells 4-ft-diameter pile shafts, and a deck area 48,216 ft 2Bridge Construction Cost: $14.5 millionASPIRE, Fall 2008 | 49

working days to complete the work andthe cost per day shown on the engineer’sestimate. This is a simple incentive for thecontractor to submit a bid with the leastamount of working days.Contractor’s Cost ReductionIncentive ProposalCC Meyers Inc., general contractor, wasawarded the contract on April 11, 2006,to build the bridge in 80 days. Thevery next day, the general contractor,along with the consultant designer andprecast manufacturer, submitted a CostReduction Incentive Proposal (CRIP) touse a non-standard, double-tee precast,prestressed concrete beam with multiplestages of post-tensioning in the field.The proposed non-standard double-teebeam was twice as wide as the originaldesign (8 ft compared to 4 ft), whichresulted in half as many girders per spanthan in the original design (total of 60girders compared to 120 girders). Astandard double-tee section is typicallysuitable for 40 to 65 ft span lengths andwas not an option in Caltrans approvedbeam sections for such long spans usedfor the replacement bridge.The proposed beam design used twostagepost-tensioning to maintaincontinuity of the superstructure underapplied loads. Cast-in-place diaphragmsA 6-in.-thick deck was cast-in-placebefore applying the second-stage posttensioning.The contractor’s consultant submittedsuperstructure design plans to Caltrans bythe end of April for review and approval.Caltran’s engineers performed independentcalculations using time-dependent concreteproperties to check stresses in the doubleteebeams during pretensioning, erection,first post-tensioning, deck casting, andsecond post-tensioning constructionstages. The independent check alsoincluded a review of deflections at variousconstruction stages, long-term camber,and superstructure seismic response. TheCaltrans independent check resulted inmodifications to the amount and locationof the prestressing.Moreover, post-tensioning a 980-ft-longcontinuous double-tee beam frameresulted in large longitudinal forces beingtransferred to the substructure pile shaftsunder service loads. These were not partpony truss bridge while the proposedalternate superstructure design wasprepared by his consultant and reviewedand approved by Caltrans. A temporarytrestle was built on the upstream side ofthe bridge to provide access to the worksite for demolition of existing bridge andthe construction of the new bridge.Construction started in early May withdriving the CISS pile shafts and buildingthe drop bent caps. Pile load testing wasconducted at two different bent locationsto determine actual in-situ soil resistance.No reduction in driving length was gainedhowever, as better than estimated soilskin friction and end bearing were notwarranted.In the meantime, new beam formworkwas built and the double-tee beams werefabricated and transported to the sitein May and June. Erection of the beamswas completed in July. The cast-in-placediaphragms and intermediate diaphragmswere cast in early August, followed bythe first-stage post-tensioning operation.The deck was cast and the second-stagepost-tensioning took place three dayslater. Work around the clock resulted inthe bridge opening to traffic on August17, 2006, one week before the schoolyear began, to the delight of the localcommunity.Special precast, prestressed concrete, double-teebeams with two-stage post-tensioning were used.between beams and first stage posttensioningwere used to create continuityunder the weight of the 6-in.-thick deckslab. A second stage post-tensioning wasapplied to carry the bridge superimposeddead and live loads. Original superstructuredepth was maintained in theproposed design and no changes weremade to the substructure design as aconsequence. Not only was the doubleteesection non-standard, but also thetwo-stage post-tensioning was not astandard practice for the precast industryin California.Caltrans immediately evaluated theproposal and approved the conceptprimarily to reduce construction time andincrease possible cost savings. Closureof the nearest precasting yard and thedifficulty of transporting long girders onthe local roads made this CRIP necessary.of the original design. Caltrans requestedthe superstructure to bent cap connectionbe modified at the two outer bents toallow for longitudinal movement duringpost-tensioning without transferring anydisplacement to the pile shafts. Metalplates with a greasy surface were usedto allow for superstructure sliding withminimal force transfer to the supportingbent caps. After initial shortening of thesuperstructure and grouting of the posttensioningducts, the connection waslocked in place.Caltrans engineers cooperated with thecontractor’s consultant to review andapprove the design and detailing of theproposed double-tee beams in two weeks.Accelerated ConstructionThe general contractor mobilizedequipment and demolished the existingTesting of pile shafts for possiblereduction in driving length._______________Ahmed M. M. Ibrahim, Linan Wang,Tariq Masroor, and Minh Ha are seniorbridge engineers, and Ofelia Alcantarais a supervising bridge engineer with theCalifornia Department of Transportation,Sacramento, Calif. The authors appreciatethe contribution of Jeffery Thorne.50 | ASPIRE, Fall 2008

2HAMILTON FORM CREATES FUNCTIONCASE STUDYESCAMBIA BAY BRIDGE“The forms work perfectly. Hamilton Formbuilds high quality,well-thought-out formsthat have contributed to the success ofmany of our projects.”Don TheobaldVice President of EngineeringGulf Coast Pre-StressThe Challenge:Gulf Coast Pre-Stress — which itself was reeling from Katrina’simpact—was awarded four major bridge projects damaged byhurricanes, including Escambia Bay Bridge near Pensacola, Florida.The bridge elements include a heavily reinforced pile cap with aunique “on-site,” cast tension connection to the precast/prestressedpile. This moment connection was designed to provide a continuousbeam configuration and provide resistance to uplift from potentialfuture storm surges.The Solution:Hamilton Form built the custom formwork including the piling,pile cap and BT78 forms. The pile cap form design includestwo-piece, tapered voids at the connection locations to allowthe top to be “popped” after initial preset of the concrete toaccommodate final stripping.The Results:The forms worked perfectly. The new bridge added anadditional line of traffic in each direction and was fullyopened ahead of schedule.To learn more about Hamilton Form visit www.hamiltonform.comHamilton Form Company, Ltd.7009 Midway Road • Fort Worth, Texas 76118 • P-817.590.2111 • F-817.595.1110

Silica Fume AssociationThe Silica Fume Association (SFA), a not-for-profit corporation based in Delaware, with offices inVirginia and Ohio, was formed in 1998 to assist the producers of silica fume in promoting its usage inconcrete. Silica fume, a by-product of silicon and ferro-silicon metal production, is a highly-reactivepozzolan and a key ingredient in high performance concrete, dramatically increasing the service-life of structures.The SFA advances the use of silica fume in the nation’s concrete infrastructure and works to increase the awareness andunderstanding of silica fume concrete in the private civil engineering sector, among state transportation officials and in theacademic community. The SFA’s goals are two-fold: to provide a legacy of durable concrete structures and to decrease silicafume volume in the national waste stream.Some of the recent projects completed by the SFA, under a cooperative agreement with the Federal Highway Administration(FHWA), include:• The publication of a Silica Fume User’s Manual—the manual is a comprehensive guide for specifiers, ready mixed andprecast concrete producers, and contractors that describes the best practice for the successful use of silica fume in theproduction of high performance concrete (HPC).• The introduction of a Standard Reference Material (SRM) ® 2696 Silica Fume for checking the accuracy of existinglaboratory practices and to provide a tool for instrument calibration. This SRM is available from the National Instituteof Standards and Technology (NIST).A much anticipated research program nearing completion by the SFA is the testing of in-place silica fume concrete underservice conditions. At the conclusion of this research the results will demonstrate the benefit of silica fume concrete’sunparalleled long-term performance. For more information about SFA, visit www.silicafume.org.QAEdison Bridge, Fort Myers, FloridaHow do you connectthe rebar?Use the…NMBSplice-Sleeve ®System.How to do it in Precast…cross-sectionQAHow is the moment connection made?All you need is an emulative detail,reconnect the concrete and rebar.Mill Street Bridge, Epping, New HampshireSPLICE SLEEVE NORTH AMERICA, INC.WWW.SPLICESLEEVE.COM11003_SPLICE_.5bridge_win08.indd 152 | ASPIRE, Fall 200811/30/07 10:51:14 AM

STAY CABLESFIGG, engineer forMaine Departmentof Transportation’sPenobscot NarrowsBridge & Observatory.Photo: FIGGnow YOU SEE US...PRESTRESSED DECK PANELSSumiden Wire is the reliablestrand supplier with TWOstrategically located facilitiesthat DELIVER NATIONWIDE andprovide experienced technicaland engineering support.YOU CAN COUNT ON US!nowYOU DON’T.SUMIDEN WIREPRODUCTS CORPORATIONEpoxy coated strand (ECS) is filledand is an ASTM productD E L I V E R S1412 El Pinal Drive Stockton, CA 95205 209.466.8924 Fax 209.941.2990710 Marshall Stuart Drive Dickson, TN 37055 Toll Free 866.491.5020 615.446.3199 Fax 615.446.8188Stressing Our Commitment To You Everyday!www.sumidenwire.com

Precast DesignThe first bridge to be constructed inthe state of New Hampshire usingthe design-build format has proven asuccess. The project also features thefirst use in the state of adjacent, voided,precast, prestressed concrete slab beamswith integral abutments combined withexpanded polystyrene (EPS) geofoamblocks behind the abutments. Theconstruction approach and designtechniques offer great potential forfuture designs that are attractive, quicklyconstructed, and cost effective.The new structure, located in Hanover,N.H., over Mink Brook, replaced anexisting steel bridge with a precast,prestressed concrete span supported onintegral abutments and a single row ofsteel H-piles driven to bedrock. Early inthe design process, the team realizedthat a precast concrete design was theonly solution capable of meeting thetight construction scheduling—but it alsoproved to be more cost effective thanstructural steel would have been.New Hampshiredesign-buildproject featuresself-consolidatingand high-performanceconcretesMink Brook Bridge featuresadjacent, voided, precast,prestressed concrete slab beamswith integral abutments.profile54 | ASPIRE, Fall 2008New Hampshire Route 10 BRIDGE over Mink Brook / Hanover, N.H.Engineer: Parsons Brinckerhoff (PB), Manchester, N.H.Geotechnical Engineering Consultant: Golder Associates, Manchester, N.H.Prime Contractor: R.S. Audley Inc., Bow, N.H.Precaster: J.P. Carrara & Sons Inc., North Clarendon, Vt., a PCI-certified producerPRESTRESSING STRAND: Strand-Tech Martin, Summerville, S.C.Awards: PCI Design Award, Best Bridge with Spans Less than 75 feet, 2007

Meets Tight Scheduleby Keith Donington, PBThe bridge’s combination of voided slabsand integral abutments eliminated the need forexpansion joints.Railing anchor bolts were preset inthe curb parapets prior to casting atthe precasting plant.Only Partial RemovalNeededThe bridge design required only partialremoval of the existing bridge beforeconstructing the new structure. Thisapproach eliminated a significant amountof in-water demolition and minimizedexcavation depths. That in turn reducedthe impact to the stream, environment,and existing slope vegetation. Theportions of the existing bridge thatremained intact were carefully selectedto allow clearance for pile-driving inaddition to serving as protection againstscour for the new substructure.Initially, the design-build team suggesteddewatering near the abutments toremove parts of the existing wingwallfoundations and to install verticalsupporting piles. That approach provedtoo difficult and jeopardized theconstruction schedule. As a result and tocompletely avoid the existing footings,the new piles were battered in both thetransverse and longitudinal directionsat both abutments. This maintainedstability of the structure during thetemporary first stage of construction aswell as for the final, as-built condition.The bridge’s combination of voidedslabs and integral abutments, whichwas adapted from a detail supplied bythe Northeast regional office of thePrecast/Prestressed Concrete Institute,eliminated the need for expansion joints.It previously had been used by the NewYork State Department of Transportationwith good results.The precast beams were set ontemporary bearing pads and madeintegral with the abutments when thebackwall concrete was placed duringthe same placement as the deck overlay.The prestressing strands extending fromthe beams and reinforcement from thedeck into the backwall resulted in a rigidconnection. Thermal movements areaccommodated by bending in the singlerow of steel H-piles oriented with theirweak axis parallel to the abutments andlocated on a line behind the existingabutment footing. This resulted in aminimum span length of 48 ft.The superstructure and integralabutments, together with the pilefoundation, act as a rigid-frame system.It was analyzed under dead and liveloads, as well as lateral loads using atwo-dimensional GT-STRUDL-basedplane frame computer model. Soil andpile stiffness together with the pointof fixity of the piles were evaluated bygeotechnical engineering consultants onthe project. Those factors were includedin the model together with stiffnessproperties of the beams and integralabutments to determine internal forces.The adjacent slab beams weretransversely post-tensioned at theabutments and midspan to helpprevent longitudinal cracking alongthe shear keys.Precast, prestressed concrete voided slab beams / New Hampshire Department of Transportation,Concord, N.H., OWNERBridge Description: 48-ft-long, single-span voided slab bridgeStructural Components: 12 typical voided slab deck beams, two fascia voided slab deck beams, and two railing-curb parapetsBridge Construction Cost: $694,805ASPIRE, Fall 2008 | 55

The use of self-consolidating concrete providedsuperior appearance and long-term durability.The bridge’s cross-section comprisesfourteen 3-ft-wide, 21-in.-deep adjacentprecast, prestressed concrete voidedslab beams constructed with selfconsolidatingconcrete, eliminating theneed for concrete vibration. The resultingconcrete is totally homogeneous witha uniform surface finish and is free of“bug” holes. It also provides a superiorappearance and long-term durability.To further enhance that durability, acalcium-nitrite corrosion inhibitor wasadded to the mix.EPS Blocks StabilizeAbutmentsEPS blocks were placed behind theintegral abutments to minimize lateralpassive soil pressure on the abutmentsand wing walls. That placement, in turn,reduced fixed-end movements at theabutments and enhanced flexibility ofthe frame system. The lateral pressurefrom the EPS blocks acting on the backface of any vertical concrete wall orbridge abutment is considered nearlyequal to zero.High-performance concrete (HPC) wasused in the 5-in.-thick deck on thebeams, rather than the more customarybituminous paving on a waterproofingmembrane. HPC also was used for theEnvironmental ProtectionThe bridge was constructed within thelimits of the New Hampshire Departmentof Transportation wetlands permit.Wildlife crossings beneath the bridgealong both banks were provided.A stormwater pollution preventionplan was prepared in compliancewith the permit requirements of theEnvironmental Protection Agency’sPhase II National Pollutant DischargeElimination System Program. The team’scontinuous coordination with theHanover Conservation Commission, whichmanages the Mink Brook Nature Preserve,ensured that the appropriate landscapingand seeding mix for restoration wouldbe implemented once the project wascomplete.The design-build approachand design techniques offergreat potential for future bridges.backwalls and approach slabs. The HPCoverlay was reinforced to integratethe beams’ backwall ends with theabutments, so the bridge could bedesigned without expansion joints.Galvanized welded wire reinforcementwas used in the concrete deck.The HPC also was used to provide asecond line of defense for the transversepost-tensioning that interconnects thebeams, helping prevent longitudinalcracking of the grouted shear keys.Such a condition has typically occurredon more heavily trafficked adjacent,precast beam-type bridges. The overlayacts compositely with the beams forsuperimposed dead loads and live loads,providing more structural efficiencycompared to a non-composite overlay.The HPC used in the approach slabsincluded pozzolan admixtures toproduce a low permeability concretewith improved durability. Using this mixeliminated the need for the customarywaterproofing membrane over the slabs,which saved time. The approach slabswere set 1-1/2 in. below finished grade,rather than level with the deck concrete,to allow for a bituminous top courseto be placed simultaneously with theroadway approach’s bituminous overlaypaving.Railing anchor bolts were preset inthe curb parapets prior to casting atthe precasting plant. This resulted inparapets that matched the beams andproduced both time savings and superiorconcrete quality.To remove the existing bridge, thedeck was longitudinally saw-cut intosections between the stringers. With acrane located behind each abutment,the beam and deck pieces were liftedonto a trailer for disposal. The existingabutments and wing walls were saw-cuthorizontally and removed above the cutwith an excavator-mounted hydraulichammer.Phased ConstructionImplementedTwo-phase construction was used toreplace the existing bridge, with trafficmaintained in an alternating one-waypattern using temporary traffic signals.Implementation of the one-way trafficpattern was delayed until after theschool year, to avoid disrupting busroutes and was removed when schoolreturned in the fall. This created a veryaggressive construction schedule basedon the amount of bridge work requiredin a limited window of time.The first construction phase involvedreplacement of the east side of thebridge. Pedestrian traffic, which wasmaintained throughout construction,was relocated to a temporary sidewalkstructure adjacent to the west fascia ofthe existing superstructure.During the second phase, when thewest side was replaced, both vehicularand pedestrian traffic used the bridge’snewly constructed east side. Pedestriantraffic was separated from vehiculartraffic using a temporary guardrailsystem installed with removable anchors.This ensured that the pedestriansremained on the west side of the traffic,which aided the flow, as sidewalks onboth bridge approaches were on thewest side of the highway.The design approach provided keybenefits to the environment whilemeeting local users’ needs forminimizing disruption and producinga cost-effective structure. Costs alsoshould be minimized throughout the lifeof the project due to the attention paidin the initial planning stages to durabilityneeds and corrosion resistance. Thisproject and its design-build approachoffer key elements that can be used inthe future in New Hampshire and inother states to reduce construction timeand both short- and long-term costs._____________Keith Donington is senior supervisingstructural engineer with PB, Manchester, N.H.56 | ASPIRE, Fall 2008

National Ready Mixed Concrete AssociationFounded in 1930, the National Ready Mixed ConcreteAssociation (NRMCA) is the leading industry advocate.Our mission is to provide exceptional value for ourmembers by responsibly representing and serving theentire ready mixed concrete industry through leadership,promotion, education, and partnering.NRMCA works in conjunction with state associations onissues such as quality, business excellence, promotion,and regulatory concerns. We strive for constant communicationon the latest information, products, services, andprograms to help our members expand their markets, improvetheir operations, and be their voice in Washington.NRMCA offers certifications for both ready mixedconcrete production facilities and personnel. Certifiedproducers strive to provide the highest quality ready mixedconcrete in the safest and most efficient ways possible.NRMCA is a principal sponsor of CONEXPO-CON/AGG.This show features over two million square feet of exhibitsincluding an information technology pavilion and anemphasis on live demonstrations throughout the exhibitareas. The show brings together contractors, producers,and equipment manufacturers at the largest exposition inthe Western Hemisphere for the construction industry.NRMCA is also the principal sponsor of the ConcreteTechnology Forum, an annual symposium on state-of-theartconcrete technologies. The Forum brings researchersand practitioners together to discuss the latest advances,technical knowledge, continuing research, tools, andsolutions for ready mixed concrete.For more information, contact the National Ready MixedConcrete Association, 900 Spring Street, Silver Spring, MD20910, 888-84NRMCA (846-7622), www.nrmca.org.Bridge MonitoringKnow more about your bridges.At Campbell Scientific, we design rugged, stand-alone dataacquisition systems for any size of bridge. From short-term testingto long-term monitoring, our systems can provide youwith valuable decision-making data.(435) 750-9692www.campbellsci.com/bridgesASPIRE, Fall 2008 | 57

CONCRETE CONNECTIONSConcrete Connections is an annotated list of websites where information is available about concrete bridges. Fast links tothe websites are provided at www.aspirebridge.org.In this Issuehttp://www.oregon.gov/ODOT/HWX/OTIAInformation about the Oregon Transportation InvestmentAct is available at this site. Click on OTIA III Bridge DeliveryProgram for specific information related to bridges.http://projects.dot.state.mn.us/35wbridge/index.htmlVisit this website for the latest information about theI-35W St. Anthony Falls Bridge and to view the on-sitewebcams.www.ncdot.org/projects/us17bypass/This North Carolina Department of Transportation websitecontains information about the U.S.17 Washington Bypass.http://environment.transportation.org/teri%5Fdatabase/This website contains the Transportation andEnvironmental Research Ideas (TERI) database. TERI is theAASHTO Standing Committee on Environment’s centralstorehouse for tracking and sharing new transportationand environmental research ideas. Suggestions fornew ideas are welcome from practitioners across thetransportation and environmental community.http://www.franklincountyengineer.org/bridge_inventory.htmVisit this site for an inventory of bridges in Franklin County,Ohio, including photographs and a description of eachstructure.Environmentalhttp://environment.transportation.org/The Center for Environmental Excellence by AASHTO’sTechnical Assistance Program offers a team of experts toassist transportation and environmental agency officialsin improving environmental performance and programdelivery. The Practitioner’s Handbooks provide practicaladvice on a range of environmental issues that ariseduring the planning, development, and operation oftransportation projects.Bridge Technologywww.aspirebridge.orgPrevious issues of ASPIRE are available as pdf files andmay be downloaded as a full issue or individual articles.Information is available about subscriptions, advertising,and sponsors. You may also complete a reader survey toprovide us with your impressions about ASPIRE. It takesless than 5 minutes to complete.www.nationalconcretebridge.orgThe National Concrete Bridge Council (NCBC) websiteprovides information to promote quality in concrete bridgeconstruction as well as links to the publications of itsmembers.www.hpcbridgeviews.orgThis website contains 50 issues of HPC Bridge Views, anewsletter published jointly by the FHWA and the NCBCto provide relevant, reliable information on all aspects ofhigh-performance concrete in bridges.Bridge Researchwww.trb.org/news/blurb_detail.asp?id=8815The U.S. FHWA’s Turner-Fairbank Highway ResearchCenter (TFHRC) has released a report that provides a briefoverview of individual TFHRC laboratories, their currentactivities, and laboratory managers.http://ntlsearch.bts.gov/tris/index.doThe Transportation Research Information Services (TRIS)online database contains over half a million records ofpublished transportation research including technicalreports, books, conference proceedings, and journalarticles.www.trb.org/CRP/NCHRP/NCHRPprojects.aspThis website provides a list of all National CooperativeHighway Research Program (NCHRP) projects since 1989and their current status. Research Field 12—Bridgesgenerally lists projects related to bridges although projectsrelated to concrete materials performance may be listed inResearch Field 18—Concrete Materials. Some completedprojects are described below:http://trb.org/news/blurb_detail.asp?id=3257NCHRP Report 517, Extending Span Ranges of PrecastPrestressed Concrete Girders, contains the findings ofresearch performed to develop recommended load andresistance factor design procedures for achieving longerspans using precast, prestressed concrete bridge girders.Spliced girders were identified as the design option withthe greatest potential for extending span lengths.http://trb.org/TRBNet/ProjectDisplay.asp?ProjectID=349NCHRP Report 549, Simplified Shear Design of StructuralConcrete Members, contains the findings of researchperformed to develop practical equations for designof shear reinforcement in reinforced and prestressedconcrete bridge girders. Recommended specificationsand commentary plus examples illustrating application ofthe specifications were also developed. The results of thisresearch have been incorporated into the AASHTO LRFDBridge Design Specifications.www.trb.org/news/blurb_detail.asp?id=8693NCHRP Report 584 Full-Depth Precast Concrete BridgeDeck Panel Systems examines recommended guidelinesand the AASHTO LRFD specifications language for design,fabrication, and construction of full-depth precast concretebridge deck panel systems. Recommended guidelines andproposed revisions to the LRFD specifications language areavailable as online appendices.58 | ASPIRE, Fall 2008

QuikDeck Suspended Access SystemBridge DivisionToll-Free: (800) 582-9391Phone: (518) 381-6000Fax: (518) 381-4613The Access Advantage for concretebridges, buildings or other structures.To be successful in today’s competitive market, you need anadvantage. The versatile QuikDeck Suspended AccessSystem’s modular platform design can be assembled fromjust a few basic components and made to fit almost anyshape or size. Designed for easy installation Safe to the environment Specially-engineered modularplatform to reduce labor costs Can be “leapfrogged” to reduceequipment cost Professional engineeringsupport and crew training oninstallation and removal toensure safetyASPIRE, Fall 2008 | 59

FHWAENHANCING THE ENVIRONMENT—Part 1by M. Myint Lwin, Federal Highway AdministrationThe Federal Highway Administration (FHWA)is committed to preserving and enhancing theenvironment through research and stewardship.In recent years, FHWA and its partners have madesubstantial contributions to the environmentand to the communities, through planningand programs that support sustainability,wetland banking, habitat restoration, historicpreservation, air quality improvements, bicycleand pedestrian facilities, context-sensitivesolutions, wildlife crossings, and public andtribal government involvement.In this and the next issue of ASPIRE, we willexplore opportunities for research, development,deployment, and education for enhancing thenatural and built environment. This articledescribes the accomplishments following thepassage of the National Environmental PolicyAct (NEPA).All photos: Shutterstock.60 | ASPIRE, Fall 2008National Environmental Policy ActIn 1969, Congress passed the NEPA toestablish a national policy for the environment,including the establishment of a Council onEnvironmental Quality.The purposes of NEPA were to• Declare a national policy that will encourageproductive and enjoyable harmony betweenpeople and the environment;• Promote efforts which will prevent oreliminate damage to the environment andbiosphere, and stimulate the health andwelfare of people;• Enrich the understanding of the ecologicalsystems and natural resources important tothe nation; and• Establish a Council on EnvironmentalQuality.More specifically, Congress tasked the FederalGovernment to use all practicable means,consistent with other essential considerationsof national policy, to improve and coordinatefederal plans, functions, programs, and resourcesso that the nation may• Fulfill the responsibilities of each generationas trustee of the environment for succeedinggenerations;• Assure safe, healthful, productive, andaesthetically and culturally pleasingsurroundings for all Americans;• Attain the widest range of beneficial uses ofthe environment without degradation, riskto health or safety, or other undesirable andunintended consequences;• Preserve important historic, cultural, andnatural aspects of our national heritage,and maintain, wherever possible, anenvironment that supports diversity andvariety of individual choice;• Achieve a balance between populationand resource use which will permit highstandards of living and a wide sharing oflife’s amenities; and• Enhance the quality of renewable resourcesand approach the maximum attainablerecycling of depletable resources.Congress also directed the President toassemble a Council on Environmental Qualityin his Cabinet and to prepare an annualEnvironmental Quality Report to Congress.Signing the NEPA on New Year’s Day of 1970,President Nixon remarked that he had becomefurther convinced that the 1970s absolutely mustbe the years when America pays its debt to thepast by reclaiming the purity of its air, its waters,and our living environment. Following the NEPA,the President introduced initiatives to improvewater treatment facilities, establish nationalair quality standards and stringent guidelines

to lower motor vehicle emissions, and launchfederally funded research to reduce automobilepollution. The President also ordered the cleanupof federal facilities that had fouled air andwater, sought legislation to end the dumpingof wastes into the Great Lakes, forwarded toCongress a plan to tighten safeguards on theseaborne transportation of oil, and approved aNational Contingency Plan for the treatment ofpetroleum spills.U.S. Environmental ProtectionAgencyHaving successfully introduced theenvironmental initiatives, President Nixondecided to establish an autonomousregulatory body to oversee the enforcement ofenvironmental policy.The President declared to the House andSenate his intention to establish the U.S.Environmental Protection Agency (EPA) with thefollowing missions:• Establishment and enforcement of environmentalprotection standards consistent withnational environmental goals.• Conduct research on the adverse effectsof pollution and on methods andequipment for controlling it; the gatheringof information on pollution; and theuse of this information in strengtheningenvironmental protection programs andrecommending policy changes.• Assist others, through grants, technicalassistance, and other means, in arrestingpollution of the environment.• Assist the Council on Environmental Qualityin developing and recommending to thePresident new policies for the protection ofthe environment.In July of 1970, the White House and Congressworked together to establish the EPA in responseto the growing public demand for cleaner water,air, and land. Having cleared all the statutehurdles, the U.S. Environmental ProtectionAgency opened its doors in Washington, D.C.,on December 2, 1970. EPA was established toconsolidate in one agency a variety of federalresearch, monitoring, standard-setting, andenforcement activities to ensure environmentalprotection. EPA’s mission is to protecthuman health and to safeguard the naturalenvironment—air, water, and land—uponwhich life depends.For more than 35 years, the EPA has beenworking for a cleaner, healthier environment.Remarkable progress has been made inprotecting human health and safeguarding thenatural environment. There is a long list ofaccomplishments including the following:• Clean Air Act to set national air quality, autoemission, and anti-pollution standards.• Agreement between the United States andCanada to clean up the Great Lakes, whichcontain 95% of America’s fresh water andsupply drinking water for 25 million people.• Clean Water Act, limiting raw sewage andother pollutants flowing into rivers, lakes,and streams.• Phase out of leaded gasoline.• Fuel economy standards and tail-pipeemission standards for cars, resulting in theintroduction of catalytic converters.• Resource Conservation and RecoveryAct, regulating hazardous waste from itsproduction to its disposal.• Superfund to clean up hazardous wastesites. Polluters are made responsible forcleaning up the most hazardous sites.• Ban on ocean dumping of sewage sludgeand industrial waste.• Pollution Prevention Act, emphasizingthe importance of preventing—not justcorrecting—environmental damage.• The National Environmental EducationAct, signifying the importance of educatingthe public to ensure scientifically sound,balanced, and responsible decisions aboutthe environment.• Clean Water Action Plan to continuemaking America’s waterways safe for fishingand swimming.• New emission standards for cars, sportutilityvehicles, minivans, and trucks.• Regulations requiring more than 90%cleaner, heavy-duty, highway diesel engines,and fuel.• Cleaner fuels and engines for off-road dieselmachinery such as farm or constructionequipment.A lot has been accomplished. A lot more isyet to be accomplished. Federal, state, tribaland local governments, industry, academia,and corporations must continue to worktogether in research, development, deployment,and education to achieve the environmentalprotection and enhancement goals set out in1970 when the EPA was formed. In the nextissue of ASPIRE, I will discuss the impact of Safe,Accountable, Flexible, Efficient TransportationEquity Act: A Legacy For Users (SAFETEA-LU).U.S. Department of TransportationFederal Highway AdministrationASPIRE, Fall 2008 | 61

Assure Quality!Specify PCICertification!PCI certification is the industry’s most proven,comprehensive, trusted, and specified certificationprogram. PCI certification offers a completeregimen that covers personnel, plant, andfield operations. This assures owners, specifiers,and designers that precast concrete products aremanufactured by companies that subscribe tonationally accepted standards and that are auditedto ensure compliance.PCI certification is more than just inspectionsand documentation. It is based on comprehensiveexpertise. For over 50 years, PCI has setthe standards and developed the knowledge forthe design and construction of precast concretestructures. This feat is set on the foundation ofmillions of dollars of research, dozens of technicalguides and manuals, a network of over 80committees, PCI’s professional and experiencedstaff, and support of over 2000 PCI members.CC o E n R f T I I d F e I E n D e cTo learn more about PCI certification and PCI,go to: www.pci.org/certificationOr callDean Frank, P.E.Director of Quality ProgramsPrecast/Prestressed Concrete Institute209 W. Jackson Blvd., Suite 500Chicago, IL 60606(312) 583-6770

Expanded Shale, Clay, and Slate InstituteThe Expanded Shale, Clay & Slate Institute (ESCSI) is the international trade associationfor manufacturers of expanded shale, clay, and slate (ESCS) aggregates produced using arotary kiln. The institute is proud to sponsor ASPIRE magazine.Sustainable concrete bridges must be durable bridges. Durable concrete must have both low permeability and fewor no cracks. Lightweight aggregate concrete has been shown to have enhanced properties in both of these issues. Theenhanced performance of lightweight concrete has been attributed to a number of factors including:• Internal curing provided by premoistened lightweight aggregate;• Elastic matching of the lightweight aggregate and hardened paste;• Excellent bond between the lightweight aggregate and paste; and• Lower modulus of elasticity and higher strain capacity.The enhanced durability of lightweight concrete, combined with the obvious benefits of reduced density, results instructures that will last longer. Such structures conserve valuable natural resources as well as scarce funds for bridgeconstruction and rehabilitation.For more information on lightweight concrete, including references discussing the factors mentioned above, pleasevisit www.escsi.org. The members of ESCSI look forward to assisting owners, designers, and concrete producers inusing lightweight concrete for bridges.Williams Pre-Stressing / Post Tensioning Systems consist of high tensile steel barsavailable in five diameters from 1" (26 mm) to 3" (75 mm) with guaranteed tensilestrengths to 969 kips (4311 kN). They are provided with cold rolled threads overall or a portion of the bar's length. All tension components for the systems aredesigned to develop 100% of the bar strength. All components of the systems aredesigned and manufactured in the United States. Williams All-Thread-Barsystems have been field proven around the world.Post Tensioning System and Prestressing Steel Bars• Transverse Post Tensioning• Longitudinal Post Tensioning• Pile Test Anchors• Ground Anchors and Soil Nails• Bridge Retrofit Applications• Seismic Restrainer Systems• Tower Base Plate Anchor Bolts• Sheet Pile Ties and Tie-backsSunshine Skyway BridgeRichmond / San Rafael BridgeWilliams Form Engineering Corp.8165 Graphic Dr.Belmont, MI 49306Phone: (616) 866-0815Fax: (616) 866-1890williams@williamsform.comwww.williamsform.comASPIRE, Fall 2008 | 63

STATELong-Span Precast U-Girders inColoradoby Michael L. McMullen, Jamal I. Elkaissi, and Mark A. Leonard, Colorado Department of TransportationI-270 Ramp over I-76: 2282 ft long, 230-ft-long maximum span, 764-ft-minimum radius.Colorado has benefited from a practiceof utilizing a broad range of structuretypes for its bridges. The Colorado Departmentof Transportation (CDOT) designers andits consultants have generally been givenwide latitude to use the structure type that isoptimal for the conditions at a particular bridgesite. Consequently, CDOT has a relative largeinventory of structural steel, precast concrete,and cast-in-place concrete bridges, with a widevariety of different sections used for these threedifferent materials.Since the 1960s, precast, prestressed concretebeams have become the structure type used mostoften because of the typical economy and generalconstruction advantages of these beams. Makingthe beams more efficient and easier to constructhas been pursued aggressively. However, precastconcrete beams tended to be used in the pastfor simpler bridges; the exceptions being theseven segmental box girder bridges used forI-70 over Vail Pass and the nine segmentalbridges through Glenwood Canyon. These wereespecially large and topographically uniqueprojects. Precast girders were generally regulatedto spans less than 140 ft and to bridges with littleor no curvature.This began to change in 1992 and hasincreased more in recent years. This year alone,CDOT will construct four precast concretebridges with span lengths over 140 ft usinghorizontally curved girders. These will be inaddition to the four existing bridges built since1995 that meet this description. The recentlycompleted I-270 bridge over I-76 is one of these.Although not the first constructed, it was thefirst bridge designed using yard fabricated,long-segment trapezoidal U-girders for a bridgewith significant horizontal curvature. “Longsegment”is used here to differentiate thesegirders from those conventionally referred toas “segmental concrete box girders” which aretypically built with shorter segment lengths.The broadened applicability of precast,prestressed concrete girders has beenaccomplished by adopting new beam shapes,increasing maximum shipping lengths, utilizingpost-tensioning for splicing, and employingcurved segments. In 1992, CDOT transitionedfrom precast I-beams with 5-in.-thick webs tobulb-tee beams with 7-in.-thick webs, permittingthe use of post-tensioning ducts. The firstprecast concrete long-segment girder splicedwith post-tensioning built in Colorado was theBuckley Road Bridge over I-76. This bridge wasconstructed in 1992 using 72-in.-deep bulb-teebeams with 96-in.-deep haunched bulb-tee piersegments.Before the Buckley Road Bridge was built,CDOT had already begun developing plans forusing precast, trapezoidal box girders for longsegmentconstruction. The Park Avenue Rampover I-25, built in 1995, and the I-225 Rampover Parker Road, built in 2000, were the firstlong-segment box girders designed in ColoradoBuckley Road over I-76: 515 ft long, three spans,183-ft-long maximum span.64 | ASPIRE, Fall 2008

I-225 Ramp over Parker Road: 1343-ft-long, 254-ft-long maximum span, 702-ft-minimum radius.to be precast. Because early fabricator interestin these sections was not certain, these bridgeswere designed giving the contractor the optionof using either precast or conventional cast-inplaceconcrete, but the contractor had to allowtraffic below the main spans during the day. OnPark Avenue, the contractor elected to use theprecast girder alternative for the main spans.These segments were cast on site and moved totheir final position during the night. The largestsegment weighed 212 tons. On the Parker Roadproject, the main span segments were cast-inplaceduring the night.The success of these two bridges helpedstimulate local fabricators’ interest in precast,trapezoidal boxes. From 1995 to 2000, CDOTdeveloped standards for precast trapezoidalU-girder sections. The sections were developedso they could be used for either straight orhorizontally curved segments and could also bepretensioned, post-tensioned, or a combinationof the two. A web thickness of 5 in. can be usedfor fully pretensioned segments and 7.5 in.to 10 in. for segments with a combination ofpretensioning and post-tensioning. Availablegirder depths vary from 48 in. to 96 in.A U-shape was selected over a closed box toeliminate the expense of interior formwork thatneeds to be removed or sacrificed. The U-shapealso facilitates having top flanges with areasthat can be readily varied from project to project.It also allows easy inspection of the interiorsurfaces in the fabricator’s yard.With the new bulb-tee and U-girder sectionsand the addition of post-tensioning for splicing,shipping weights became the primary limitationon segment lengths. In 2001, CDOT workedwith local fabricators and shipping and erectionsubcontractors to upgrade maximum shippingweights from 85 tons to 120 tons. This wasespecially significant for the U-girders giventheir greater weight per unit length.In addition to economics, aesthetics andconstructability have been central aspects ofthese changes to precast girders. Trapezoidal boxgirders became especially popular starting inthe 1970s. CDOT responded by providing thesesections using structural steel, cast-in-placeconcrete, and short-segment segmental bridges.Cast-in-place concrete has been especiallyversatile for providing a variety of trapezoidal boxgirder sections for different conditions includinglong spans and complicated geometry. The newprecast U-girder sections provided CDOT with acompetitive alternate to structural steel girdersin terms of cost, on-site construction time, andappearance. The recently completed I-270 Rampover I-25 in Denver is an example of the elegancethat can be obtained with trapezoidal boxes.The project was bid using a contractingmethod where a fully detailed default design wasprovided in the plans and specified contractordesign-build alternatives to the default wereallowed. In this case, the default design wasa steel box girder bridge and the successfulcontractor elected to use the precast U-girderdesign-build alternative.Precast U-girder — group II pretensioned or post-tensioned.ASPIRE, Fall 2008 | 65

Conventional short-segment, precast concretebox girder bridges provide a trapezoidal boxsection and also the means for constructionwithout the heavy influence of falsework inhigh traffic areas. The Hanging Lake Viaduct inGlenwood Canyon is one of the most popularbridges in Colorado for its appearance. The newprecast U-girder standards, however, can providea competitive alternate to these bridges. TheU-girder sections are now commonly used inColorado for bridges of all sizes. Three precastconcrete fabricators in Colorado have theformwork necessary to readily produce thesesections—making them competitive for small,as well as very large projects.The State Highway 52 over I-25 Bridge is anexample of a smaller project using the U-girdersand built in 1999. This was the first vehicularI-270 Ramp over I-25: 1424 ft long, 200-ft-longmaximum span, 950-ft-minimum radius.bridge in Colorado constructed using shopfabricated precast U-girders. This bridge is astriking example of the clean details that canbe obtained for a simple grade separation withlong-span concrete U-girders, and by simplyordering the girders from a local fabricator.State Highway 52 over I-25: 322 ft long, 3 spans,190-ft-long maximum span.I-70 Hanging LakeViaduct: 6396 ft long,208-ft-long maximumspan, 1650-ft-minimumradius.I-70 Trinidad Viaduct: NB 1985 ft long, SB2058 ft long, 256-ft-long maximum span,1000-ft-minimum radius.The I-70 Trinidad Viaduct, currently underconstruction, is an example of a large projectusing the U-girders. Here again, CDOT employeda default design with specified contractor designbuildalternatives. The default design was fora conventional short-segment concrete boxgirder bridge. The successful contractor electedthe design-build alternative using the precastU-girders provided by a local fabricator.Looking to the future, there are a numberof enhancements CDOT would like to see.Strong-backs were used on the Buckley RoadBridge for splicing the girders without the use ofshoring towers. Further developments to allowsplicing the girders in the air would improveconstruction options. On the Trinidad Viaduct,full-width precast deck panels were used toeliminate forming the bridge deck overhangs.Other developments to reduce deck formingwould reduce on-site construction time. ThePark Avenue Bridge had significant verticalcurvature and twisting superelevation, but wasformed on-site with plywood. Form innovationsthat could push the limits of girder geometrywould be desirable. The Parker Road Bridgeused fiberglass reinforcement and carbon fiberprestressing strands for the precast deck panels.Future use of non-corrosive reinforcement andprestressing strands would enhance durability.Having a large arsenal of different structuretypes readily allows for superstructureoptimization for the cost, constructability, andappearance needs of a particular bridge site.The relative recent developments with precastconcrete, especially the development of precastU-girders, has significantly strengthened CDOT’sarsenal of potential solutions.______________________Michael L. McMullen is supervising bridge designengineer, retired; Jamal I. Elkaissi is supervisingbridge design engineer; and Mark A. Leonardis state bridge engineer with the ColoradoDepartment of Transportation.For more information on Colorado bridges,visit www.dot.state.co.us.66 | ASPIRE, Fall 2008

COUNTYThe new King Avenue Bridge over the OlentangyRiver incorporates modern design while reflectingthe history of the earth-filled arch that it replaced.Photos: Franklin County Staff.Creating and Maintaining CIVIC PRIDE inFranklin County by James A. Pajk, Franklin County, OhioThe Franklin County Engineers Officeis responsible for the inspection andmaintenance of 363 bridges. With a populationgreater than one million residents, numerouscommunities in the county have redevelopedtheir historic districts, many of which havecrossings that enter into these areas. Throughthe public involvement process, Franklin Countyunderstands the importance of creating gatewaysinto these communities. The use and innovationof modern concrete bridge engineering hashelped our office achieve goals of maintainingand creating structures with civic value.The existing structures along the Olentangyand Scioto Rivers were designed and built as aresult of the 1908 City of Columbus Master Planand the 1913 flood. Structures on Lane Avenue,Third Avenue, and King Avenue were multispan,earth-filled reinforced concrete barrelarches. A plan was developed to replace eachstructure and to design a bridge to complementits surrounding community.Most municipalities and civic groups wishedto preserve the structures that they perceive asgateways. The need to expand infrastructurefacilities made preservation difficult. Ultimately,the new structures retained the aestheticelements of historic significance while usingmodern construction techniques. Each newstructure was designed with an expected serviceLane Avenue over the Olentangy River serves as agateway to Ohio State University. The two-span,cable-stayed bridge limited environmental impacts,and the use of concrete allowed the contractor tocomplete the project 5 months early.Franklin County crews fabricated concrete slabs andstay-in-place railing panels for the Dublin RoadBridge to expedite construction.life of 100 years and all incorporate concrete asthe predominant material. Concrete, whetherit is pretensioned, post-tensioned, or simplyreinforced, allowed us to expand our creativethinking in terms of appearance and design.Precasting was also used to achieve a high levelof quality control, limit construction time, andminimize impacts in environmentally sensitivestreams.The design for the King Avenue Bridge overthe Olentangy River was selected to reflect thehistory of the bridge that it was replacing. Thebridge serves as the south entrance to Ohio StateUniversity. Public opinion led the design team tocreate a five-span segmented, precast concretearch. This structure type was the first of its kindin Ohio. Seventy individual precast arch ribsections were post-tensioned by the precaster,connected at midspan by a diaphragm, andpost-tensioned together. Precast, prestressedbox beams were used to span from pier seatsto arch seats. The high-performance concretedeck has transverse post-tensioning to limit deckcracking.Lane Avenue, which serves as the mainentrance to Ohio State University, was to bewidened from three to five lanes of traffic. Amore modern bridge was selected to reflectrecent expansion of university facilities andlessen environmental impacts. The result wasa stunning two-span, cable-stayed bridge withpost-tensioned concrete trapezoidal tub girders.The use of concrete allowed the contractor anopportunity to better control the schedule andopen the bridge 5 months early.Franklin County is fortunate to have threebridge maintenance crews very capable offabricating and constructing concrete structures.We take pride and satisfaction in the work theyperform. From late fall to early spring, barringa heavy snow season, crews precast concretecomponents for future contract projects.For our Dublin Road Bridge, the crewsfabricated concrete slabs and stay-in-placerailing panels to expedite construction and limitthe amount of formwork for the railings. Eachprecast concrete slab unit was unique in size andlength. The railing panels were match cast forthe fascia slab units.For the Clifton Avenue superstructurereplacement, the crews precast traffic barrierand wall panel sections using formliners. Theuse of these precast elements on contractorsupplied precast, prestressed concrete box beamswith a composite deck allowed the project to becompleted in four months.County crews also fabricate four-sided andtwo-piece, four-sided box culverts for replacementstructures. The two-piece units consist of precastbottom slabs with a keyway and three-sidedunits, which are placed on top of the bottomslab with the joints staggered. Using two-pieceunits reduces the weight and allows smallerequipment to be used in the field.Franklin County also has an aggressiveconcrete sealing maintenance program. Allconcrete barriers are cleaned and sealed with anon-epoxy silane every 5 years. In addition, allmajor concrete decks are sealed with a solublereactive silicate to limit the penetration of saltsand oils into any deck cracks.In conclusion, our office will continue to useconcrete as a material that will satisfy the needsof our constituents for generations to come.___________________James A. Pajk is Franklin County deputy engineer,bridges in Columbus, Ohio.ASPIRE, Fall 2008 | 67

AASHTO LRFDLoad Modifierfor Ductility, Redundancy,and Operational Importanceby Dr. Dennis R. MertzArticle 1.3.2.1 of the LRFD BridgeDesign Specifications introduces aload modifier, which is the product of factorsrelating to ductility, redundancy, and operationalimportance. The original intent of this loadmodifier was to encourage enhanced ductilityand redundancy. Operational importance wasincluded to provide additional reliability formore important bridges.When the first edition of the LRFDSpecifications was written, research into theeffects of ductility and redundancy on the safetyor reliability of bridges was not available. Thus,the factors were subjectively chosen as discussedin the Commentary C1.3.2.1. These subjectivechoices were also considered to be conservativeby the specification writers. Since the writingof the first edition, research into the effects ofredundancy on reliability has been completedthrough NCHRP Projects 12-36, Redundancyin Highway Bridge Superstructures, and12-47, Redundancy in Highway BridgeSubstructures. This research has yet to beimplemented in the LRFD Specifications. It hasbeen partially implemented in the forthcomingAASHTO Manual for Bridge Evaluation assystem factors on the resistance side of the loadand resistance factor rating (LRFR) equation,especially in the provisions for rating segmentalconcrete bridges.A limited study of the effects of the specifiedload modifier on the resulting reliability of95 girder-bridge configurations is reported inArticle C1.3.2.1. The results from the study areas follows:Reliability Index as aFunction of Load ModifierLoad Modifier, η Reliability Index, β0.95 3.01.00 3.51.05 3.81.10 4.0The placement of the load modifier, whichreflects ductility and redundancy on the load sideof the LRFD equation, may seem counterintuitiveas ductility and redundancy are characteristics ofthe resistance and not the load. The modifier wasplaced on load side and not on the resistance sidefor a practical reason as they must be related to themaximum and minimum load factors of Table3.4.1-2 used for permanent loads. This relationshipis illustrated in the following equations:For permanent loads increased by themaximum load factor:η i= η Dη Rη IFor permanent loads decreased by the minimumload factor:1η =iηηηD R Iwhereη i= load modifier: a factor relatedto ductility, redundancy, andoperational importanceη D= a factor related to ductility asdefined in Article 1.3.3η R= a factor related to redundancy asdefined in Article 1.3.4η I= a factor related to operationalimportance as defined in Article 1.3.5The notion of the load modifier, at least interms of ductility and redundancy, may becounter to traditional bridge designer thought.Traditionally, bridge designers are taughtthat sufficient ductility and redundancy mustbe provided; differing degrees of ductility andredundancy are not typically considered. Forexample, bridges are categorized as redundantor non-redundant. Thus, the concept of loadmodifier has not been embraced by the practicingbridge engineering community. Typically, bridgeowners specify that the load modifier be taken as1.00 and that the basic requirements for ductilityand redundancy in the LRFD Specifications besatisfied. Any enhancements to ductility are notconsidered to reduce the specified loads, andnon-redundant structures are not allowed. Suchowner-specified reactions to the load modifier ofthe LRFD Specifications can be found in manystate bridge design manuals.68 | ASPIRE, Fall 2008

Bayshore Concrete Products

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