ASPIRE Summer 08 - Aspire - The Concrete Bridge Magazine

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READER RESPONSEI am currentlyworking on thep r e l i m i n a r yengineering forthe rehabilitation of anw w w . a s p i r e b r i d g e . o r gT H E C O N C R E T E B R I D G E M A G A Z I N EProtecting Against & EvaluatingSPRING 2008FIRE DAMAGE!DES PLAINES RIVER VALLEYBRIDGE ON I-355MAROON CREEK BRIDGEREPLACEMENTLOOP 340 BRIDGESTAXIWAY SIERRA UNDERPASSLemont, I linoisState Highway 82, Aspen, ColoradoWaco, TexasSky Harbor Airport, Phoenix, Arizonahistoric concrete arch bridge in the Pittsburgharea. Part of the scope of the project is acomplete re-decking. Due to both difficult accessand the benefits of shorter project duration,we believe that a precast deck alternativemay be appropriate. Fortunately, I happenedto see in the Fall 2007 ASPIREmagazinea very similar-looking project, the MonroeStreet Bridge. The precast plank subdeck witha CIP topping is pretty much exactly what Ihad envisioned as the way to go here. I waswondering if it would be possible to getmore details from this project, whether it isconstruction photos or engineering drawings.I’m particularly interested in reinforcementand dowel details at the floor beams and anydetails with regards to the sidewalk cantilevers.I have proposed details to our client, but nothaving seen a similar job, I think their mindwould be set at ease to see details on a similarjob that has been built successfully. Please letme know if it would be possible to get any ofthis information. I appreciate your assistance.Gary Gardnerms consultants inc.[Editor’s Note: Mr. Gardner was put in touchwith the participants in the Monroe Street Bridge,Spokane, Wash., and we trust all questions andrequests were answered.]Indiana LTAP is a research/technology transferprogram funded by INDOT and FHWA. Wepublish a quarterly newsletter and are interestedin requesting permission to reprint an articlefrom your Winter 2008 issue “StructurallyDeficient Bridges are SAFE.” How might I goabout requesting that permission?Lisa Weicker CalvertWest Lafayette, Ind.I work at the University of Arkansas at Little Rockin the department of Urban Studies & Design. Weare seeking your permission to print the articletitled “Fifth Street Pedestrian Plaza Bridge” fromthe Winter 2008 edition of ASPIRE, in a report weare producing for the City of Little Rock.Kim SimmonsUniversity of ArkansasLittle Rock, Ark.The “Loop 340 Bridges” article in the Spring2008 ASPIRE is great! I was very pleased we wereable to get that project to letting in August 2004,the month before I retired. I’m now equallypleased to see it in ASPIRE.Mary Lou RallsRalls Newman LLCAustin, Tex.ZBar ad_ASP_JUN08_half pg vert3:Aspire 5/28/08 9:03 AM Page 1THERMALLYAPPLIED ZINCINNER COATING...Durable; providingcathodic protection forthe steel as needed.HIGH PERFORMANCECORROSION PROTECTIONREINFORCING 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.ELECTROSTATICALLYAPPLIED POWDER OUTERCOATING... ZBAR’s first lineof defense against water andchlorides which lead to corrosion.I recently had an opportunity to read theSpring 2008 edition of ASPIRE. I was somewhatdisappointed that there were no articles dealingwith railroad bridges. As a Rail Bridge Designer,I know that the U.S. railroads use a large volumeof prestressed concrete beams and girders fortheir bridges. There are some amazing thingsthat the railroads do with their bridge designsand construction using these types of beams andgirders. One of the most amazing is that theycan change out bridge superstructures in hours,not days or weeks. I believe your readers wouldbe fascinated with what railroads can do withprestressed concrete elements.Jeffrey TeigHDR Engineering Inc.Omaha, Neb.ASTM A1055 COMPLIANTStandard Specification for Zinc and EpoxyDual Coated Steel Reinforcing Bars.MEETS FHWA HIGHWAY FOR L.I.F.E. REQUIREMENTSCALL 888-637-9950FOR SALES & ORDERING INFORMATIONwww.gerdauameristeel.com/zbar4 | ASPIRE, Summer 2008

FOCUSPARSONS adapts to theMARKETby Craig A. ShuttFrom Tacomato Abu Dhabi,Parsons useslocal expertiseto create efficient,attractive designsParsons operates around the world,conquering tough logistical challengesand delivering landmark projects in manycountries and climates. But while it worksglobally, it designs locally. Designers takeadvantage of the expertise available ineach area to ensure that they create themost efficient, durable, and aestheticallypleasing structure.“Parsons is a diverse company, withdiverse capabilities,” says Greg Shafer,southeast subsector manager in theBaltimore office. The company’s servicesinclude bridge planning, design, andconstruction of all types, includingdesign-build programs. It providesconstruction engineering and inspection,bridge rehabilitation and retrofit, andcondition inspection and seismic analysis.That combination keeps the companyinvolved in bridges at all stages of theirlife cycle, providing a good perspectiveon the industry.“We work pretty hard to investigate alltypes of construction when we begin aproject, including precast concrete, cast-inplaceconcrete, segmental precast girders,and structural steel. We always consideralternatives, and our choice usuallydepends on the region and conditions.If the contractors are familiar andcomfortable with a specific technology, itis more attractive to design that way.”8 | ASPIRE, Summer 2008

Designers on theSoutheast CorridorTransportationExpansion Project(T-REX), the largesttransportationcontract in Coloradohistory, reconfiguredthe interchange tomove light-rail trainsfrom the highestlevel to the lowest.The changes resultedin significant costsavings, aestheticimprovements, andenhanced temporarytraffic control.Photo: Parsons andColorado Departmentof Transportation.New Techniques ContinueDesigners expect the dominance ofconcrete in their projects to continue,especially as new engineering techniquesare unveiled. The Woodrow WilsonBridge, for instance, used lightweightconcrete on the deck slabs for its movablespan. “When moving a big mass like that,it makes a lot of sense to use lightweightmaterials wherever possible,” says Shafer.“We used lightweight concrete combinedwith normal weight mixtures to create anefficient system that took advantage ofthe best properties of both.” Weight alsobecomes a concern for large componentsthat must be transported and lifted underchallenging conditions, he notes.Low water-cementitious materials ratiosalso are being used more often, he says.“We can achieve a nice, low permeabilitymix by using a lower ratio and improvedcuring techniques. These help providebetter durability, which is in demandtoday.” High-performance concrete (HPC)also helps meet challenging goals, headds. “We’re using HPC more and more,because it provides strength that cancreate longer spans and eliminate piers.But it’s also being used more often for itsdurability, which helps when the clientwants a 100-year service life.”The designers also are intrigued by theadvancements being made in reinforcingsteel. Stainless-steel strand, such asused on the Woodrow Wilson Bridge,is becoming more popular, along withgalvanized and epoxy-coated options.“The idea of stainless-steel reinforcement,both in solid forms and as a claddingover a carbon steel core, creates realpossibilities,” says Shafer. “They arerelatively new technologies that arestill not readily available or always costeffective,but we expect to see themmore and more.”As their volume increases, the prices willcome down, adding more demand—which will increase volume and helpdrop the price further. Adds Goryl,“There is a lot of research going on withreinforcement in concrete. We sometimesget into complex designs that push thelimits, and we like to see new techniquescome out.”As those techniques arrive, Parsons willwork with local contractors and concretesuppliers to find the most efficientsolution. “We always look at what localconcrete producers are accustomed toproviding,” says Shafer. “We ask if theyhave experience with certain techniquesto ensure we are specifying somethingthat can be built in the local businessclimate.”That approach ensures the design createsthe most efficient approach possible, saysShafer. “New techniques and growingfamiliarity with them in new areas go along way toward giving owners whatthey want, which is something that willlast a long time and save them money inthe long run.”For more information on this or otherprojects, visit www.aspirebridge.org.ASPIRE, Summer 2008 | 13

PERSPECTIVESustainableConcrete Bridge Designby Jay Holombo, Vinh Trinh, and Maher K. Tadros, PBS&JAs with many states, California isfaced with diminishing open spaceto improve congested transportationnetworks. Therefore, most of theseimprovements involve heavily-congestedurban interchanges, where trafficdisruption is not acceptable. Efforts arefurther hampered with constructioncost increases in recent years that havelargely outpaced inflation; thus delaysin project delivery effectively diminishavailable budgets. All of this underscoresthe importance of delivering sustainableconcrete bridges both cost-effectivelyand in an accelerated schedule. Bridgeconstruction is often in the critical pathof larger transportation improvementprojects and is a significant portion ofthe overall project cost.When owner agencies and industrycollaborate, the cost benefits ofsustainable concrete bridge deliveryare maximized, as demonstrated by therecently completed widening of theState Route 22 freeway in SouthernCalifornia. Twenty-two bridges werewidened, nine bridges were replaced,and three new bridges were added in anaggressive design-build schedule. Thesebridge improvements were part of anoverall project to eliminate bottlenecks,reduce congestion, and improve safetyon a 12-mile stretch of Route 22,located in Orange County, California,extending from Valley View BoulevardFormwork is placed around precastgirders in the construction of a seismicresistantintegral connection with thecolumns. Photo: Jay Holombo, PBS&J.Completed low-profile precast concrete girder undercrossing on SR 22.Photo: Vinh Trinh, PBS&J.to its terminus at State Route 55. Thisproject added a high-occupancy vehicle(HOV) lane, auxiliary lanes, shouldersalong with ramp replacement, andinterchange reconfiguration.The $670 million project was fundedby the Orange County TransportationAuthority (OCTA), and delivered usingdesign-build, led by the Granite-Myers-Rados (GMR) joint venture. The GMRteam hired PBS&J as the lead structuralengineer in design and constructionsupport. A collaborative environmentfacilitated by innovative project deliverymethods was crucial in not only meetingthe aggressive design-build schedule butalso maximizing economy.A significant challenge on the projectwas maintaining acceptable verticalclearance of the undercrossing andseparation widening because widenedbridge structures had to match theexisting cross-slope and profile. Further,the widened structures had to matchthe structural seismic and gravityresponse characteristics of the existingcast-in-place box girder bridges thatare both continuous longitudinally andmonolithic with the substructure. Andfinally, disruptions to traffic had to beminimal during construction.14 | ASPIRE, Summer 2008

Agency-Industry Collaboration MaximizesEconomic Benefits in CaliforniaTo meet this challenge, the designbuildteam worked with OCTA and theCalifornia Department of Transportation(Caltrans) to select a system of precast,prestressed concrete bridge beamsand stay-in-place (SIP) precast concretedeck panels with a composite concretetopping. Depending on the spanrange, bulb tees, California I-beams,and rectangular-shaped girders wereutilized. The latter were used forshorter spans, where vertical clearancenecessitated the use of bridge-specificgirder depths, and exterior bridgebeams to match the aesthetics of theexisting cast-in-place bridges. Continuityfor gravity and seismic loading wascreated with longitudinal reinforcementin the cast-in-place deck topping andbottom-flange continuity reinforcementmechanically coupled through the capbeammaking an integral connectionwith the columns. This system allowedthe design-build team to expeditedelivery economically while meeting thestructural performance and aestheticrequirements.One of the biggest challenges waswidening the State Route 22/I-5separation structure. This bridge spans17 lanes of I-5 traffic on a curvedalignment with a variable superelevationup to 6%, and on a 45-degree skew.The longest span is 170 ft, has an insideradius-of-curvature of 1300 ft andspans five lanes of mainline northboundI-5 traffic that had to remain openthroughout the duration of the project.The design-build team elected to usecurved precast, prestressed concretetub girders to span over these lanes oftraffic. These girders, measuring over100 ft in length and weighing over 250kips, were spliced with box girders caston falsework using continuous posttensioning.The contractor site-castthe curved tub girders using a cast-inplaceconcrete slab that was graded sothe soffit would match deck contoursincluding the variable super-elevationand camber. Vertical stems were usedto simplify the interface with the castin-placesections. After casting, thesegirders were transported from thecasting site, and lifted into place usinga single crane. Although not necessarilynew, the curved tub girder systemallowed for an innovative structurethat was economical, fit the aestheticrequirements of the site, and met theaggressive design-build schedule withminimum traffic interruptions. Savingsamounted to approximately 10% of theoverall bridge cost; however, this methodhad an added benefit of minimizing riskand providing a safer choice.The challenges faced by agenciesand industry, as more and more ofour transportation improvements inCalifornia include highly congestedurban interchanges, require innovativeand cost-effective solutions to meetCurved precast, prestressed concretespliced girders span I-5 at theinterchange with State Route 22.Photo: Rick Sharp, PBS&J.diminishing budgets. Constructionmaterials and reduced cost escalation haslargely outpaced inflation. To meet thesechallenges, agency-industry collaborationis essential in the delivery of sustainableconcrete bridges, and the benefits of thiscollaboration have been demonstratedwith successful delivery of the StateRoute 22 HOV widening.Aerial view of State Route 22 passing over I-5 during construction.Photo: © James A. Gallego.

PROJECTONE OF ELEVEN,BUT ONE OF A KINDby Mark A. Gaines and Joseph M. Irwin, Washington State Department of Transportationand Michelle L. Tragesser, ParametrixThe floating Hood Canal Bridgespans alone over saltwaterThe 1.5-mile-long floating bridge is built to withstandhigh winds, strong currents, and moves daily with thetidal fluctuations. The Hood Canal Bridge is a vitallink between the Olympic and Kitsap peninsulas thateliminates using multiple ferries or driving 60 milesusing land routes.profileHood Canal Bridge / Kitsap and Jefferson Counties, Wash.Engineer: Washington State Department of Transportation, Olympia, Wash.Prime Contractor: Kiewit-General (a joint venture), Poulsbo, Wash.Concrete Supplier: Glacier Northwest Inc., Seattle, Wash.Post-Tensioning Supplier for Strand Tendons: AVAR Inc., Campbell, Calif.Post-Tensioning Supplier for Bar Tendons: Williams Form Engineering Corp., Portland, Ore.Precaster for Prestressed Girders, Stay-in-Place Deck Panels, and Voided Slabs:Concrete Technology Corporation Inc., Tacoma, Wash., a PCI-certified producer16 | ASPIRE, Summer 2008

The pontoons are heavily reinforced and posttensionedin all three principle directions.Tight tolerances on placement of formworkand reinforcement are required to maintainthe design height of the pontoon deckabove the water surface.The scene is the epitome of thePacific Northwest: evergreen trees, darkblue water, and majestic mountains. Butthe natural beauty of the Hood Canalhides a beast’s heart. As winter descendson the region, it brings icy rains, galeforce winds, and white-capped wavesthat blow and crash through the areaalmost unimpeded.At the northern end of the waterway,the Hood Canal Bridge spans acrossthe divide to connect the Kitsap andOlympic peninsulas, fluctuating inelevation daily with tidal shifts up to16.5 ft. Its elevated roadway, like bridgeseverywhere, allows drivers a more directroute to their destinations. Yet, thebridge is one of only 11 floating bridgesin the world. With a length of 7869ft—approximately 1.5 miles—the bridgeis the longest of its kind over saltwater.It hasn’t been an easy existence, either.The 1979 StormThe original Hood Canal Bridge’s westhalf sank in 1979 after less than 18years of service. With the wind blowingfrom the south and a very strong currentflowing from the north, the west-halffloating structure overturned at the mostexposed part of the canal. That half wasreplaced in 1982, but now the east half,completed in 1961, is reaching the endof its service life.Why Build a FloatingBridge?At the bridge site, the canal is up to340 ft deep. A concrete floating bridgeprovides a cost-effective solution forcrossing a channel with very deep, softsoils in a high seismic region. While ahigh-level structure was evaluatedduring design, the exorbitant costs forthe site conditions could not be justified.Not only must the bridge float in aharsh marine environment, it must alsopermit marine vessels to navigate thecanal. Essential hydraulic, electrical,and mechanical components housed inkey pontoons allow the bridge to openits 600-ft-wide draw span for marinetraffic. With a naval submarine baseto the south of the structure and themouth of the canal to the north, thisfunction is critical for national security.A total of 14 floatingpontoons are beingconstructed in fourseparate cycles inapproximately2-1/2 years in thegraving dock.Two pontoons incorporated precastsegments and closure pours to facilitateplacement of large, heavy embeddedmechanical components of the drawspan that required maximum tolerancesof 1/16 in. in 500 ft.Construction ProgressThe Hood Canal Bridge West-HalfRetrofit and East-Half ReplacementProject was started in June 2003 andwill be completed by the end of 2010.The new east half is expected to beoperational until 2084. To ensure this75-year lifespan, high-performancePrecast concrete floating bridge / Washington State Department of Transportation, Olympia,Wash., OwnerEpoxy-Coated Strand Supplier: Sumiden Wire Products Corp., Stockton, Calif.Bridge Description: 1.5-mile-long floating bridge with fixed approach spans and movable transition spans between fixed piers on land andstructures floating on tidal saltwaterConcrete Structural Components: Prestressed concrete pontoons; reinforced concrete anchors; two-column reinforced concrete piers;32-in.-deep and 42-in.-deep, precast, prestressed concrete I-girders; and precast, prestressed concrete stay-in-place deck panels topped with a cast-inplaceconcrete roadwayBridge Cost: $471 millionASPIRE, Summer 2008 | 17

WSDOT Moving TowardsPerformance-BasedConcrete SpecificationsAlthough the concrete has performedwell overall, future projects similarto this will use performance-basedconcrete specifications. This willallow WSDOT to include additionalperformance requirements such asshrinkage and scaling resistance. Somepotential improvements that couldbe made to this mix include reducingcementitious materials content, addingshrinkage-reducing or corrosioninhibitingadmixtures, or perhapsmoving to self-consolidating concrete.Shifting to performance specificationswill allow contractors to develop mixesthat meet performance requirementsyet are tailored to the forming,placement, consolidation, and the formremoval methods they prefer.The WSDOT is currently consideringuse of the performance-basedspecifications for the next floatingbridge project, which will likely bethe State Route 520 floating bridgereplacement across Lake Washington.This project is currently in the designphase, with pontoon constructionexpected to start late 2009. Pontoonconstruction on this project sharesmany similarities with the Hood Canalproject. The WSDOT is incorporatingvaluable experiences from Hood Canalinto the design of the State Route 520Bridge to further improve performanceand constructability, and reduceconstruction costs.materials and tight constructiontolerances are required. Wideningand improving the bridge’s west halfwas completed in 2005, Since then,the Washington State Departmentof Transportation (WSDOT) has beenconstructing a new east half, which willbe moved into place in May-June 2009,and further upgrading the west half.The work is underway at multiplec o n s t r u c t i o n s i t e s i n w e s t e r nWashington. Since early 2006,construction pro g ress includessuccessfully building and floating 12 ofthe 14 new east-half pontoons, joiningthe draw span pontoons together, andrehabilitating three 1980 pontoons.The original elevated roadways wereremoved from these pontoons, andwider roadways with a new profile gradewere constructed in their place. Also, 20gravity anchors have been constructedand were placed on the canal floor insummer 2007. Other large operationsin various stages of construction includefabrication of the transition spans andspecialized supports, lift spans, largespherical and cylindrical bearings,major mechanical components, andoutfitting of the draw span assemblywith buildings, access ramps, and thehydraulic, mechanical, and electricalsystems.All of these elements of work set thestage for the closure of the bridge inMay-June 2009, when the east half ofthe bridge and the west transition spanwill be replaced. The bridge will be opento traffic while new anchor cables areinstalled and west half mechanical andelectrical upgrades are made.Pontoon ConstructionThe prestressed high-performanceconcrete (HPC) pontoons are beingconstructed in four separate cycles atConcrete Technology Corporation’sgraving dock in Tacoma, Wash. Thelargest of the cellular box structures is60 ft wide, 18 ft tall and 360 ft long.The pontoons are heavily reinforcedwith both conventional epoxy-coatedreinforcing steel and longitudinal,transverse, and vertical post-tensioningtendons.The HPC used for the pontoons wasoriginally developed in the 1990s forthe I-90 Lacey V. Murrow (LVM) floatingbridge across Lake Washington andincludes the following components:Type I/II cement: 625 lb/yd 3Class F fly ash: 100 lb/yd 3Silica fume: 50 lb/yd 3Aggregates: 1/2-in. maximum sizeThe approximately 31,000 yd 3 ofpontoon concrete have a minimumspecified 28-day compressive strengthof 6500 psi, and a maximum 56-daychloride permeability of 1000 coulombs.The actual 28-day compressive strengthshave been approximately 11,000 psiand the 56-day permeability less than800 coulombs. Early in the project, thecontractor realized that the LVM concreteplacement in the pontoon walls wouldbe challenging because the walls are upto 21 ft tall; 6 in., 8 in., and 10 in. thick;and heavily congested with reinforcingsteel and post-tensioning ducts. Toimprove concrete placement andconsolidation, the contractor requestedapproval to exceed the maximum 9-in.slump that was allowed by the contract.This was achieved by using additionalhigh-range water-reducing admixturewithin manufacturer’s allowances. AfterThe elevated roadway was constructed atTerminal 91 at the Port of Seattle on threeexisting pontoons. These three pontoonswere used temporarily in the west drawspan until 1982 to open the Hood CanalBridge quickly after the 1979 storm sunkthe west half. These pontoons weresuccessfully rehabilitated in 2007 after25 years of storage in the Puget Soundand are used in the new east half.

The final set of 10 anchors was towed to the Hood Canal and set accurately on the channel floorusing GPS, tilt meters, and gyroscopes. The anchor cables will be attached between the anchorsand pontoons in 2009.A concrete floating bridge providesa cost-effective solution.Pontoons are assembled together withspliced post-tensioning tendons beforebeing towed to the Hood Canal Bridge toreplace the old pontoons.conducting a series of qualification testsand constructing a mock-up pontoonwall, the contractor successfullydemonstrated that this “new” mixcould be placed without segregation.Testing and acceptance of this concretewas accomplished using the flow testthat is common with self-consolidatingconcrete (SCC).Another innovation implemented was toprecast portions of two pontoons thatmake up the moveable draw pontoons.These pontoons have heavy mechanicalcomponents cast into the walls 21 ftoverhead. The precasting operationimproved overall safety in supportingthese massive guides and facilitated thetight alignment tolerances needed forthe mechanical draw span operations.The precast elements consisted ofportions of the exterior walls with allnecessary reinforcement and posttensioningto tie into the top andbottom slabs. Once the precast pieceswere set into place, reinforcement andpost-tensioning was tied into the baseslab and the wall closure regions. Thebase slab, wall closures, and top slabwere then constructed with cast-inplaceconcrete. By precasting portionsof these pontoons, construction timewas reduced. Precasting also allowedmuch of the work to be shifted off-siteand away from the heavily congestedgraving dock facility.Elevated RoadwayConstructionTo withstand the regular pounding ofsaltwater waves that crash over thebridge during the storm season fromOctober through April, the elevatedroadway built atop the pontoonsis constructed primarily of reinforcedand precast, prestressed concrete.With project activities since early 2006focusing on constructing pontoonsand anchors and assembling the drawspan section, the elevated roadwayremains a main element of work to beaccomplished.The elevated roadway on a floatingstructure compels the designer to selectan optimal span length to minimizethe dead loads and to evenly distributecolumn loads to the pontoon structure,which behaves like a beam on elasticfoundation from water buoyancy. Forthe Hood Canal Bridge, this equates toshallow I-girders with 60-ft span lengths.Built on two-column piers, the two-spancontinuous units have a hinge diaphragmat the center pier. The floating structure isisolated from seismic events with specialconnections to the fixed structures, so thefloating bridge is governed by dynamicloads from wind, waves, and currentsinstead of seismic loads.The prestressed concrete I-girders aretypical WSDOT 32-in.- and 42-in.-deepsections, but all reinforcement and0.5-in.-diameter prestressing strands areepoxy coated and the bottom flangeconcrete clear cover is 1-1/4 in. The7-1/2-in.-thick roadway deck consistsof 4 in. of reinforced concrete cast on3-1/2 in.-thick, stay-in-place precast,prestressed concrete deck panels.Using stay-in-place panels significantlydecreased the time required to constructthe deck and increased safety whenworking over water.ASPIRE, Summer 2008 | 19

Girders on the draw pontoons, wherethe profile grade drops to the lowestpoint, use dapped ends and endblocks—with some cantilevering overpiers. To open the navigation channel,three lift spans are raised to allow thedraw pontoons to retract underneath.The draw span necessitates minimizingthe deck elevation while maintainingsufficient vertical clearance formaintenance vehicles underneath andto clear most storm waves.Temporary ballast water is used in thepontoon’s internal cells to balance thepontoons as the superstructure loadsare added. Regular monitoring of thepontoon freeboard (distance from topof the deck to water line) is needed tomaintain a level and stable structure atdockside. Specialized survey equipmenttracks the top plane of the deck as itmoves with the wind, waves, and theaddition of new loads. Constructionmeasurements are then referencedto this fluctuating theoretical plane.Permanent rock ballast is used to makefinal adjustments.Gravity AnchorConstructionFrom the public’s perspective, thereinforced concrete gravity anchorswere said to look like giant “tea cups,”measuring 29 ft tall and rangingin diameter from 46 ft to 60 ft. Theanchors are massive, stout vessels thatmust float initially. Built in Seattle, thelarge bowl-like structures were towed50 miles to Hood Canal, then loweredto the canal floor and filled with crushedrock ballast.The draw spans open for large vessels and submarines in the Hood Canal.The ballasting is required to attain thefinal submerged anchor weight, keepingthe pontoons in alignment during stormswithout shifting the anchors on the softsoil slopes. While the geometry of theanchors is complex, the general designdetails are straightforward. The anchorshave 3 in. of concrete clear cover to allreinforcement and a low-permeability,4000 psi concrete mix made with peagravel. Vertical post-tensioned bartendons are used in the walls at thepicking eye locations to distribute theshear forces from the setting operations.After the new east half of the bridgeis floated into place, 3-in.-diameteranchor cables will be threaded throughthe 27-in.-diameter pipe cast inside4.5-ft-thick, heavily reinforced walls andattached to the pontoons to complete theanchorage connections for the floatingbridge. Some of the gravity anchors areoffset nearly 2000 ft from the bridgealignment and rest in water as deepas 340 ft below mean tide. Cathodicprotection systems are used to protectthe anchor cables, thereby protecting thepontoons and the anchors.Floating into the FutureFrom the anchors 340 ft below thewaterway’s surface to the pontoonsand elevated roadway, the concreteof the new Hood Canal Bridge willbe tested regularly by the elements.High-performance concrete and theextensive use of pretensioning and posttensioningwill ensure that it passes itsdaily trials. The WSDOT has been able tolearn from its past experience to create anew structure that has set the standardfor floating bridges in the Washingtonstate highway system and beyond. Thenew Hood Canal Bridge is a balance ofform and function, putting innovativeideas into action and paving the way forimproved transportation well into thefuture._____________Mark A. Gaines is assistant stateconstruction engineer and Joseph M.Irwin is communications consultantfor the project with the WashingtonState Department of Transportation,Olympia, Wash. Michelle L. Tragesser iswith Parametrix, Tacoma, Wash., and istechnical services manager for the projectThe elevated roadway uses precast,prestressed concrete I-girders, and stay-inplacedeck panels. This construction methodreduced formwork efforts and improvedsafety for the over-water constructionactivities.For more information on this or otherprojects, visit www.aspirebridge.org.20 | ASPIRE, Summer 2008

BRIDGESFORLIFE ®FEATURING HIGH-PERFORMANCE BRIDGES2008 PCINATIONAL BRIDGECONFERENCEU.S. Department of TransportationFederal Highway AdministrationCosponsored by the Federal Highway AdministrationThe PCI National Bridge Conference (NBC) is the premiernational venue for the exchange of ideas andstate-of-the-art information on concrete bridge design,fabrication, and construction—particularly precast,prestressed concrete bridges. Public agenciesand industry have joined forces and are committedto bringing together the nation’s most experienced,expert practitioners. More than 90 papers will be presentedin 23 individual sessions. The NBC will be heldin conjunction with the PCI Annual Convention andExhibition, which offers additional opportunities.Sunday afternoon, October 5Opening Session featuring the 2008 PCI BridgeDesign Award PresentationsSpotlight State Plenary Session – The WashingtonState Department of TransportationMonday, October 6Technical Education SessionsTuesday, October 7Technical Education SessionsSocial Events and GatheringsThroughout the event, you’ll have ample time tonetwork with colleagues and establish or renewacquaintances. Social events include an openingreception gala, sumptuous buffet luncheons sponsoredby our exhibitors, and a banquet. Above all,you’ll have the opportunity to immerse yourself inthe state of the art of concrete bridges. An excitingprogram of tours and activities for accompanyingguests is also available.Special BonusThose registering for the National Bridge Conferencealso have the opportunity to participate in all the excitingcommittee meetings and educational sessionsof the PCI Annual Convention and Exhibition.For a listing of papers and presenters, and to viewregistration details as they develop, visit the conferencewebsite atwww.pci.org/news/bridge_conference/index.cfm.For more information, contact John Dick;Tel.: (312) 360-3205; Fax (312) 786-0353; orEmail: jdick@pci.org.OCTOBER 5–7, 2008, ROSEN SHINGLE CREEK RESORT, ORLANDO, FLA. PLAN NOW TO ATTEND!CON08-1192_HalfPgAd.indd 16/12/08 4:06:58 AMASPIRE, Summer 2008 | 21

Replacement of the I-10 Bridgesacross Escambia BayInnovative Solutionsfor Rapid Constructionby Charles Rudie, John Poulson, Victor Ryzhikov, and Theodore Molas, PB AmericasFollowing HurricaneIvan, emergencyrepairs were made tothe westbound bridgeusing spans from theeastbound bridge.All Photos: CharlesRudie, PB.Hurricane Ivan struck Florida’s coast inSeptember 2004 near Pensacola withdevastating results. More than 50 spansof the existing 3-mile-long, I-10 bridgesacross Escambia Bay were washed intothe bay and another 60 were permanentlydislocated. In order to reopen I-10 tothe public as quickly as possible, missingspans on the westbound bridge werereplaced with entire spans from the moreheavily damaged eastbound bridge.With the westbound bridge reopened,work shifted to the eastbound bridge.By replacing the missing spans of thesuperstructure with a temporary metalstructure, the eastbound bridge wasbrought back into service, but for onlyone lane of traffic.T h e F l o r i d a D e p a r t m e n t o fTransportation (FDOT) quickly releaseda request for proposals (RFP) for thedesign-build replacement of the I-10bridges. The request mandated thatall traffic be moved onto the newstructure by the end of 2006, and thatthe bridges be brought to their finalcondition consisting of three 12-ft-widelanes of traffic with two 10-ft-wideshoulders no later than the end of 2007.The width of this typical section allowedfor one bridge to temporarily carry four12-ft-wide lanes and a center barrieruntil the second structure was finished.Design-Build ApproachWith notice to proceed given on AprilprofileI-10 Bridge Replacement / Escambia Bay, Fla.Engineer: PB Americas, Tampa, Fla.Prime Contractor: Tidewater Skanska Flatiron, Milton, Fla.Precasters: Standard Concrete Products Inc., Tampa, Fla., a PCI-certified producer; Gulf Coast Pre-Stress Inc.,Pass Christian, Miss., a PCI-certified producerPost-Tensioning Contractor: VSL, Hanover, Md.AWARDS: 2007 PCI Bridge Design Award for the Best Bridge with Spans Greater than 150 ft.22 | ASPIRE, Summer 2008

25, 2005, the design-build team hadless than 21 months to design andbuild the first new bridge. Both bridgeswould need to be completed in just 33months. These milestones forced thedesign schedule to be very aggressiveand to be split into several submittals.This allowed the precaster and theprime contractor to begin operationsearlier than a traditional process wouldhave allowed. The first submittal wasdelivered on May 20, 2005, clearingthe way for pile fabrication and driving.The entire plan set was completed inSeptember, just 5 months after notice toproceed.SubstructureSeveral options were considered for thefoundation, but 36-in.-square precastconcrete piles were determined to bethe most efficient and economical.The typical span could incorporate fivepiles located directly under five girders,allowing for a more efficient pile capdesign.The use of precast elements wasinstrumental in achieving the project’smilestones. Precast elements not onlyeliminated time-consuming cast-inplace(CIP) construction on the water,but also allowed the contractor toutilize two precasters. The majority ofthe substructures consisted of precastpile caps resting on five piles. The othersubstructures were piers with waterlinefootings, which increased in size asthey approached the channel. For alarge number of the piers, two precastfootings resting on three piles wereused. This arrangement kept the weightof the footings to 80 tons, allowing thecontractor to use the same equipmentto erect precast piles, caps, footings,and girders.The 36-in.-square piles have a 22.5-in.-diameter void throughout the length ofthe pile, except for a 4-ft solid sectionat the tip. This was done primarily forreduction in material and weight, but italso presented the opportunity to utilizeprecast pile caps and footings. Theconnection between the substructureelement and the pile was made byinserting a rebar cage into the top 10 ftof the pile that extends into the pile cap,or footing. With a plug that extends6 in. below the cage, the void wasthen filled with concrete. The length ofconnection was controlled by the stresstransfer between the precast concreteof the pile and the CIP concrete of theplug.Production piles were completed forthe channel piers first. This was donebecause the spliced girders requiredsubstantially more time to erect than therest of the superstructure. The footingsfor these piers needed to be cast-inplace,and the contractor employed avery clever method to accomplish this.First, a concrete seal slab was cast in theyard to create the bottom form. Next, aprefabricated rebar cage was placed onthe seal slab. Steel side forms were thenconnected to the seal slab. The topsof the side forms were connected toeach other with a series of steel girders.These girders were then connected tothe seal slab with four steel tie rods.These rods were placed inside PVC pipesto accommodate removal after casting.This entire system was then lifted intoplace and set on top of the piles. Thesteel girders rested on top of steel pipes,which were placed on the piles. Thisprocess eliminated the need for frictioncollars on the piles and transferred theentire load down to the pile throughcompression. After the concrete wascast and given time to set, the steelpipes and tie rods were removed andthe remaining holes filled.After the footings were finished,work proceeded on the remainderof the substructure. Except for thepreviously mentioned precast pile caps,the remainder of the substructurewas cast-in-place. The majority of thereinforcement in the columns, caps, andstruts was pre-tied in the yard, or on abarge. As the formwork was erected,these pre-tied cages were set into place,making the elements ready for concretequickly.Spliced post-tensionedhaunched girderswith a drop-in spanwere used for the250-ft-long main spans.Precast, prestressed concrete / Florida Department of Transportation, Tallahassee, Fla., OwnerBridge Description: Two 2.6-mile-long parallel bridges with precast, prestressed concrete beams and cast-in-place concrete deckwith the first bridge completed in 20 monthsStructural Components: 1024 78-in.-deep Florida bulb tees, 71 AASHTO Type II girders, 6 AASHTO Type I girders,130 pile caps, 64 pile footings, 1346 3-ft-square piles, and 8 2-ft-square pilesDesign and Construction Cost: $245.6 millionASPIRE, Summer 2008 | 23

Precast, prestressed concrete girders with acast-in-place deck were the obvious choice.SuperstructureThe superstructure selection was heavilyinfluenced by the RFP’s requirementthat the typical span length of thebridge had to be a minimum of 130ft and the channel span length hadto be a minimum of 250 ft. This spanarrangement, and the aggressiveenvironment created by the saltwater inEscambia Bay, made precast, prestressedconcrete girders with a cast-in-place deckthe obvious choice for the superstructure.For the typical span, five 78-in.-deepFlorida bulb tees at a 12 ft 6 in. spacingand a length of 136 ft were the mosteconomical. A three-span post-tensionedspliced girder based on the 78-in.-deepFlorida bulb tee was chosen for thechannel span.The spliced girder is comprised of fivesections: two haunched sections overthe center piers, two end sections, anda drop-in girder between the haunchedsections. The haunched sections overthe center piers increase to a maximumdepth of 112 in. The system contains fourdraped post-tensioning ducts to housetwelve 0.6-in.-diameter Grade 270 lowrelaxationstrands. To handle the burstingstresses associated with these strands,the end beams contain an approximate2-1/2-ft-wide by 10-ft-long anchor blockover the full depth of the beam.A deck stripper was used to remove thesteel formwork from the underside ofthe deck.Before erection of the segmentscould occur, two temporary shoringtowers were constructed to supportthe system between the end girdersand the haunched girders. After thehaunched and end girders were erected,the drop-in section was set into placebetween the haunched girders. Thedrop-in segment rested on two strongbackssupported from the tops of thehaunched girders. Once all the segmentswere in place, the strands in the firsttwo post-tensioning ducts were stressed.At this point, the deck was placed. Afterthe deck achieved sufficient strength,the strands in the last two ducts weretensioned. This erection sequenceafforded minimum disturbance to thebarge traffic in the channel.Deck ConstructionAfter the girders were set anddiaphragms cast, work shifted to theCIP deck. Two methods were employedfor the placement of formwork utilizedin the deck construction. The first wasa removable steel formwork system,which was installed with a track-drivenformwork placer. The tracks for theplacer were temporarily placed on thegirders. The placer used a system ofwinches to lift formwork, drive it intoposition, and hold it in place as workerstightened a series of turnbucklesto allow the formwork to rest on thebottom flange of the girders. Aftercasting the deck, the formwork wasremoved by a formwork stripper. Thestripper drove over the deck on rubbertires and employed an under-slung armto access the formwork from belowthe deck. The stripper used a system ofhydraulic jacks, winches, and a slidingplatform to remove the formwork andtransport the sections to the top ofthe deck for future use. At the peak ofconstruction, this method allowed thecontractor to place over 10,000 ft 2 ofbridge deck per day.The second formwork method utilizedwas corrosion resistant stay-in-place (SIP)forms. The use of SIP was approved forthe approaches and over the channel toallow deck construction from multiplefronts.A track-driven placer was used to installthe steel formwork for the deck.Working on multiple fronts wasnot unique to deck construction.The extremely aggressive scheduleassociated with the project requiredthe contractor to utilize this philosophyon all aspects of construction. At thepeak of construction, over 20 craneswere on site with a work force of over350 people working day and night tocomplete the first bridge.ConclusionInterstate 10 provides the travelingpublic with a vital link between Floridaand the southeastern United States. I-10functions as a major corridor for thedelivery of goods and services, and alsoas an essential evacuation route. Theimportance of reestablishing this linkcould not be said more simplisticallyand truthfully than as stated by theformer governor of Florida, Jeb Bush,at the ribbon cutting ceremony for theeastbound bridge, “This was a big damndeal!” These bridges will stand as atestament to what can be accomplishedwhen a crisis challenges the tenacityand perseverance of the bridge buildingcommunity.___________________Charles Rudie, senior structural engineer;John Poulson, vice president; VictorRyzhikov, senior supervising engineer;and Theodore Molas, senior structuralengineer are all with PB Americas,Tampa, Fla.For more information on this or otherprojects, visit www.aspirebridge.org.24 | ASPIRE, Summer 2008

HPC Bridge Views Is 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.comASPIRE, Summer 2008 | 25

AvoidingLANDSLIDESby Kevin Harper, CaliforniaDepartmentof TransportationThe emergency projectrelocates a portion of U.S.Route 101 away from alarge landslide requiringtwo large bridges overthe South Fork Eel River.The large landslide extends over1000 ft above the river envelopingthe current highway. The slide isapproximately 3000 ft wide.Photos: © Caltrans.The relocationof U.S. Route 101required two highlevelbridges overthe Eel RiverAn emergency project to relocate aportion of the Pacific Coast Highway(U.S. Route 101) away from a largelandslide in northern California requiredtwo large bridges to span the SouthFork Eel River. Although the bridges arewithin a quarter mile of each other, theyare dramatically different structures. Thedifference in the bridge types resultedfrom the vastly different terrains at thetwo crossings of the South Fork Eel Riverthat snaked along in the shape of agiant “U” with a bridge over each leg.The southern leg of the river, with itswide banks, required a 1355-ft-long,three-span, segmental concrete bridgethat was 275 ft above the river. Thenorthern leg of the river, which passedthrough a narrow rock walled canyon,required a 581-ft-long, three-span, caston-falseworkconcrete arch bridge thatsits 150 ft above the river.Route 101 is the primary route thatprovides direct access to California’snorth coast for commercial truckingand recreational traffic. North of theSan Francisco Bay area, this highwayis considered the “lifeline of theCalifornia’s north coast.” There has beena recurring problem of landslides aroundConfusion Hill over the last decade,resulting in frequent road closuresand high maintenance costs. When amajor landslide occurs that closes bothlanes, the traffic south of Confusion Hillmay have to backtrack and detour anadditional distance of 250 miles. Duringthe past 10 years, over $33 million hasbeen spent on slide repairs.The project involves relocatingapproximately 1.5 miles of U.S. Route101 away from the active landslide. Thelarge ancient rockslide complex extendsprofileSouth Fork Eel River Bridges (Confusion Hill Bridges) / Leggett, Calif.Engineer: California Department of Transportation, Sacramento, Calif.Prime Contractor: MCM Construction Inc., North Highlands, Calif.Contractor’s Segmental Engineer: Finley Engineering Group Inc., Tallahassee, Fla.Concrete Supplier: Mercer-Fraser Company, Eureka, Calif.Form Traveler Supplier: AVAR Construction Systems Inc., Campbell, Calif.Post-Tensioning Supplier: Schwager Davis Inc., San Jose, Calif.Reinforcing Steel Supplier: Fontana Steel, Stockton, Calif.26 | ASPIRE, Summer 2008

upwards from the river for more than1000 ft, enveloping the current highwaythat is benched into the mountain about240 ft above the river. The landslidearea is approximately 3000 ft wide.Geotechnical studies have concludedthat the slide is progressively losingstrength and there is a high probabilitythat the complex will continue to movein the future. This highway relocationproject is an emergency project that isfully financed with federal emergencyrelief funds. The expedited deliveryof this $65.7 million dollar projectonly took 28 months from the initialplanning study phase until award of theconstruction contract.The complete project includes twobridges, two tieback retaining walls, anda large cut between the two bridges.The bid for the structures work was$49.4 million. The contractor startedwork in June of 2006 and is expected tocomplete the project in 2009.North BridgeThe smaller north bridge is a concreteinclined leg frame arch with a 229-ftcenter span and 175-ft end spans. Thisbridge type fits this particular site wellby meeting the requirement to keepthe piers out of the ordinary high waterlimits of the river while still maintainingbalanced span ratios. This configurationactually kept the piers out of the higher100-year water level, which simplifiedthe environmental process even more.The river at this site was containedwithin a relatively narrow canyonwith steep rock walls, which providedsuitable foundation material to anchorthe inclined piers. The superstructureof the bridge is a cast-in-place, posttensioned,two-cell box girder withsloping exterior webs. The box varies indepth from 13.8 ft at the piers to 5.9ft at the ends and midspan. The deckwidth is 42.8 ft and the bottom slabwidth varies from 16.8 ft at the piersto 24.7 ft at the ends and midspan.The bridge was cast on falsework thatwas up to 140 ft tall. The solid concretetapered piers are anchored into themountain in 17.5-ft-wide by 6.9-ft-highby 80-ft-deep mined shafts to developthe full probable plastic moment ofthe piers during a seismic event. Theshafts were excavated through very hardrock that required blasting, as well asweathered and fractured rock regionsthat required rock bolting for stability.Concrete compressive strengthwas specified as 6100 psi for thesuperstructure and 5100 psi for thepiers. The concrete strength required attime of post-tensioning was 3600 psi.The south bridge, which is 275 ft abovethe river is a cast-in-place concretesegmental box girder constructed by thebalanced cantilever method.Photos: © Jon Hirtz, Caltrans.The north bridge, which is approximately 150 ftabove the river, was built as a cast-on-falsework posttensionedconcrete box girder. The lower portion ofthe falsework (table top) can still be seen below thebridge as well as the temporary access trestle behindthe bridge.The total post-tensioning jacking forceapplied at abutment 1 for the full-lengthtendons was 8776 kips. The tendonsconsisted of 0.6-in.-diameter, 270 ksi,low relaxation strands.South BridgeThe larger south bridge uses a cast-inplace,segmental concrete box girderwith normal weight concrete. Likethe north bridge, the piers were notonly outside the required ordinaryhigh water limits of the river, but alsothe 100-year flood levels. The southbridge was selected to be segmentalbecause its height above the river wastoo high for economical constructionusing falsework. The span lengths of thebridge are 348 ft, 571 ft, and 436 ft.Segmental cast-in-place concrete / California Department of Transportation, OwnerDrilling Subcontractor: Pacific Coast Drilling, Petaluma, Calif.Earth Work and Mined Shafts: Ladd & Associates, Redding, Calif.Bridge Descriptions: Three-span, segmental cast-in-place concrete single cell box girder constructed by the balanced cantilever method andthree-span, cast-on-falsework post-tensioned concrete two cell box girder with inclined piersStructural Components: South Bridge: 68 concrete segments in spans of 348 ft, 571 ft, and 436 ft. North Bridge: Cast-in-place on falseworkwith spans lengths of 175 ft, 229 ft, and 175 ftBridge Construction Cost: South Bridge—$37 million; North Bridge—$9 millionASPIRE, Summer 2008 | 27

For both bridges, the piers were locatedoutside the 100-year flood levels.Looking south at segmental constructionof the south bridge pier 2 cantilever withform travelers. Abutment 1 can be seenin the background. Photo: © Jon Hirtz,Caltrans.The superstructure varies in depth from31.5 ft at the piers to 11.5 ft at theends and midspan. The single cell, boxgirder cross section has vertical websand is post-tensioned longitudinallyand transversely. The box girder has adeck width of 42.8 ft and a bottomslab width of 23.8 ft. The bridge isbeing built by the balanced cantileverconstruction method from each pierand casting on falsework near theabutments. The contractor is utilizingone set of conventional form travelers,constructing the pier 2 cantilever firstand then moving the travelers over topier 3 to construct the final cantilever.The cantilevers on each side of thepiers consist of 17 segments. The firstfour heavier segments are 13.1 ft longwhile the remaining 13 segments ofeach cantilever are 15.4 ft long. Theclosure segments are 12.5 ft long. Theheaviest segment weighs 200 tons. Thepier table length is 45 ft and is 7.5 ftout of balance toward the center spanside of the pier so that during segmentproduction the cantilever will not bemore than one-half of a segment out ofbalance. The first segment cast is on theend span side of the piers.The heights of the piers from top of thefooting to the top of the bridge deckare 200 ft. Because of this height, it wasdetermined that it was more economicalto use a hollow pier section. Thehollow piershave heavilyconfined cornerelements usingw e l d e d N o .10 reinforcinghoops spacedat 4-3/8 in.o n c e n t e r sto get the necessary ductility to meetthe California Seismic Design Criteria.The solid pier footings and caps wereclassified as mass concrete and requiredchilled water to be pumped through theelements to keep the heat of hydrationbelow specified limits. The footingsincorporated eleven 5-ft-diameter castin-drilledhole piles. The piles are upto 136 ft deep and have a nominalcompression resistance of 4382 tons perpile. The footing dimensions are 36 ftlong by 49 ft wide by 10.5 ft deep.Construction of the superstructurebegan at the pier 2 table in October2007. Early on, the contractor was ableto achieve two segments per week perpair of travelers on the first cantilever.The contractor has plans to increasesegment production to three segmentsper week prior to completing this firstcantilever. The bridge deck incorporatesan integral overlay in which an additional1 in. of cover has been provided to thedeck reinforcement for profile grinding.The bridge has also been designed tocarry a future wearing surface.The design of the bridge utilized the1990 CEB-FIP Model Code for ConcreteStructures to model the time-dependentcreep and shrinkage characteristics ofthe bridge. Testing of the contractorsmix surprisingly showed that the actualshrinkage was twice that predicted in theTypical section for the cast-on-falsework north bridge.The depth varies from 13.8 ft at the piers to 5.9 ft atthe ends and midspan. Photo: © Caltrans.Rendering of thecompleted south bridge.Pier 2 is on the right side of photo. Photo: © Caltrans.

Protecting the EnvironmentThe project is located at the northend of Mendocino County. It is withinthe majestic redwood forests nearStandish-Hickey State Recreation Area,approximately 10 miles north of thetown of Leggett where State Route 1terminates and joins U.S. Route 101.Several tourist attractions are nearbyincluding the adjacent Confusion HillMystery Spot from which the landslidegets its name.The South Fork Eel River is federallydesignated as a “Wild and Scenic River.”Because of this designation, all bridge pierswere required to be outside of the “ordinaryhigh water” level of the river in order toexpedite the environmental process on thisemergency project. This requirement causedthe bridges to have relatively large centerspans over the river. Both bridges are threespanstructures that carry two lanes of trafficand have see-through concrete barriersalong each edge of the deck.Advertisers IndexAVAR........................ 39Bentley/LEAP .. . . Inside Front CoverCampbell Scientific.. . . . . . . . . . . 51DSI. ........................ 43Eriksson Technologies.....Back CoverFinley Engineering.. . . . . . . . . . . . 29FIGG .. . . . . . . . . . . . . . . . . . . . . . . . 3Gerdau Ameristeel.............. 4Hatch Mott MacDonald ........ 33Lehigh Cement................ 25PB . ......................... 7PCAP—CABA..... Inside Back CoverSplice Sleeve. ................ 33Stalite....................... 49Standard Concrete Products..... 21T.Y. Lin International .. . . . . . . . . . . 5VSL .. . . . . . . . . . . . . . . . . . . . . . . . 38CEB model. Consequently, a shrinkagereducingadmixture was added to themix to cut the concrete drying shrinkagein half. The shrinkage results of the mixat the Devil’s Slide segmental bridgeswere similar (see article in Winter 2008ASPIRE), and a shrinkage-reducingadmixture had to be incorporated intothat mix as well.The project is progressing on scheduleand within budget. The north bridgewas completed in January 2008.The contractor is currently truckingexcavated material from the large cutsbetween the two bridges over thenorth bridge. The south bridge pier 2cantilever is expected to be completedin July, at which time the form travelerswill be moved over to pier 3. The closurebetween the cantilever tips is scheduledto be placed in early 2009._______________________Kevin Harper is a senior bridge engineerwith the California Department ofTransportation, Sacramento, Calif.For more information on this or otherprojects, visit www.aspirebridge.org.SPIRE_adfinal.indd 1ASPIRE, Summer 3/3/08 2008 6:43:22 | PM 29

ECONOMICAL BRIDGEWIDENINGby Craig A. ShuttTwo types of concretegirders were combinedto create an economicaldesign that complementssurrounding structuresDesigners faced several key challengesin planning the widening of State Route22 over the Garden Grove Boulevardin Orange County, Calif. A key concernwas complementing other bridges alongthe highway, which were constructedwith cast-in-place concrete box girders,while remaining within a tight budget.The solution was found in using twotypes of precast concrete girders, whichalso helped overcome other obstacles.The $500-million project was part ofan extensive revamping of State Route22, which serves as a key regional routethrough some of the most denselypopulated areas of the county. Thebridges accommodate local vehicularand pedestrian cross-traffic within thecommunities bisected by the freeway.In all, 34 bridges and more than100 retaining walls and soundwallswere included in the project, whichprofileGarden Grove Boulevard Widening / Orange County, Calif.Engineer: URS Corporation, Roseville, Calif.Prime Contractor: GMR (a joint venture of Granite Construction, C.C. Myers, and Rados), Orange, Calif.Precaster: Pomeroy Corp, Perris, Calif., a PCI-certified producerAwards: Best Rehabilitated Bridge in the Precast/Prestressed Concrete Institute’s 2007 Design Awardscompetition30 | ASPIRE, Summer 2008

The bridge was widenedfrom three lanes to fivein each direction.The project involved several key challengesthat required innovative thinking.constructed, reconstructed, widened,or modified the infrastructure along 12miles of highway. The overall projectwas undertaken on a design-build basisand bid as a lump sum contract.Widened by One-ThirdThe existing bridge, built in 1960, wasconstructed of cast-in-place, reinforcedconcrete box beams, as were manyof the bridges along the route. Theconstruction widened the six-lane bridgeby one-third to accommodate a total of10 lanes of traffic. Each side along thebridge’s 340-ft length was widened by28.75 ft, creating a total width of 170ft. The deck’s total area expanded by19,500 ft 2 to 57,800 ft 2 . The bridgefeatures two 61-ft-long end spans andtwo 108.75-ft-long main spans. Thestructure also includes a high skew angleof 59 degrees and a tangent-horizontalalignment, with a 1% grade.The project involved several keychallenges that required innovativethinking, says Syed Mohsin Kazmi,senior project manager for URS Corp.in Roseville, Calif., the bridge designer.These went beyond aesthetics to includeboth logistical and safety issues thatrequired close teamwork among thedesign and construction partners.Specifically, the city and Orange CountyTransportation Authority officials wantedto ensure traffic was not disruptedthroughout the project, build the projectquickly, blend it with other cast-in-placebridges along the highway, and keep itwithin tight budgetary restraints.To resolve these issues, the designersspecified two types of precast concretegirders for each of the four spans oneach side of the original bridge. Theoutside girder on each side is a 5-ft-deeprectangular, hollow, precast, prestressedconcrete girder. The three interior girderson each side are 5-ft-deep precast,prestressed concrete bulb-tee girders.Approximately 250 precast concretepanels were used for the deck, withfour precast domes used for decorativepilasters.The girders were erected on cast-inplacebent caps, which sit on cast-inplacecolumns and footings. They, inturn, are supported by 366 precast,prestressed concrete, driven piles thatwere 14 in. square. “The soil in this arearequired the addition of piles to providethe necessary support for the additionalloads of the columns for the widenedbridge,” Kazmi explains.“It was a huge challenge to design andconstruct this project, because of thevariety of concerns involved,” he adds.“The selection process for these projectsis very rigorous in any event, but welooked at many alternatives before wefound the one that provided the bestcombination of benefits. The challengewas especially to come up with astructure type that could be constructedquickly and without significant impactto the existing traffic.”The exterior beam is a rectangularsection to match other bridges,whereas, more economical bulb-teesare used for the interior beams.Precast, prestressed concrete girders and deck panels / California Department ofTransportation (Caltrans), OwnerBridge Description: Widening of a four-span cast-in-place concrete bridge with precast, prestressed concrete rectangular box beams,bulb-tee girders, and deck panelsStructural Components: Twenty-four, 5-ft-deep precast, prestressed concrete bulb-tee girders; eight, 5-ft-deep rectangularhollow precast, prestressed concrete girders; 250 precast, prestressed concrete deck panels, 366 14-in.-square precast, prestressed concretedriven piles; and four precast domes for decorative pilastersASPIRE, Summer 2008 | 31

Precast, prestressed concrete beams were used because of a lack of clearancefor falsework and to speed construction.Limited Vertical ClearanceOne of the significant logistical concernswas the inadequate vertical clearanceavailable for using falsework. Using castin-placebox girders to replicate the lookof the existing bridge and surroundingstructures would have required falseworkspanning three traffic lanes in eachdirection, he explains. “The availablevertical clearance was not adequate toaccommodate falsework deep enoughto span three lanes of traffic. This wasthe key factor in choosing precastconcrete.”The girders and deck panels also offereda shortened construction time, as theycould be fabricated off-site and erectedquickly upon arrival. “The precast girderssignificantly reduced the timeframe forimpacting on-going traffic,” he says.The project was designed in six months,with construction taking about 1 year.But the actual road closure to erect theprecast girders amounted to only 2 daysduring this period.Although cast-in-place girders could notbe used due to falsework requirements,the concern was that the use of precast,prestressed concrete bulb-tee girderswould not blend with the appearanceof the rest of the bridge, or with otherbridges in the area. “We usually seecast-in-place box girders being used inCalifornia, and the agencies involvedin this project wanted to match theirdesign,” Kazmi explains.To replicate that look, precast, prestressedconcrete rectangular box girders wereused as the exterior girder on each side ofthe bridge. The girders were deeper thanthey were wide and featured a roundedoutside fascia corner to replicate the lookof cast-in-place box girders. The designprovided the box shape that all the bridgesoffered to drivers nearing the structures,he says. Inside girders, which are viewedonly when cars are directly beneath them,are bulb-tee sections. “Motorists see thelook of a concrete box-girder bridge asthey approach, and the structure blendswell with the adjacent structures.” Thiscombination of girders kept the cost ofthe project in line by using less expensivebulb-tee girders in the less visible area, henotes.AestheticsThe existing structure and several structures along the corridor arecast-in-place box girder bridges with vertical webs for the exteriorgirders. The use of more typical precast, prestressed concrete girdersat this location would not have matched the aesthetic characterof the bridges. The problem was addressed by the use of precast,prestressed concrete rectangular box girders with a rounded outsidecorner for the exterior girders. This gives the motorist the look of aconcrete box girder bridge and the structure blends well with theadjacent structures.Speed of Construction and Public SafetyAnother challenge on this project was the need for a structuretype that could be built quickly and would significantly reduce theduration of the inconvenience to the on-going traffic. This was largelyachieved by the efficient use of precast, prestressed concrete girdersas well as permanent precast concrete deck panels.32 | ASPIRE, Summer 2008

While preparation work was underwayat the site, the girders were cast at theprecaster’s Perris, Calif., plant. Oncethey arrived at the site, all 32 girderswere erected in 2 days, while the roadunder the bridge was closed and trafficrerouted. Traffic could flow under thebridge while the precast concrete deckpanels were being installed. “Beingable to keep traffic open while thedeck panels were installed provided aconsiderable advantage.”The project achieved all the goals set forit, by combining several types of girdersand maximizing the benefits offeredby the precast concrete design. “Therewere a number of factors that createdkey challenges on this project,” saysKazmi. “But solutions for all of themwere made possible because of the useof precast concrete members.”Economical, Efficient&Elegant SolutionsBridge ServicesPlanningDesignInspectionRehabilitationProgram ManagementConstruction ManagementWorldwide Expertise & Local ExperienceMillburn, NJ 973.379.3400Pleasanton, CA 925.469.8010Pensacola, FL 850.484.6011Mississauga, ON 905.855.2010For more information on this or otherprojects, visit www.aspirebridge.org.Hatch MottMacDonaldRobert ShulockPractice Leader, Highways & Bridges206-855-0968QAEdison 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 111/30/07 10:51:14 AMASPIRE, Summer 2008 | 33

An artist’s rendering showsthe bridge from theWest Virginia side.State Partnership CreatesCable-StayedOhio DOT buildsbridge connectingstates, then turnsover operation toWest VirginiaWhen the steel cantilever throughtrusssteel bridge over the Ohio Riverbetween Pomeroy, Ohio, and Mason,W.Va., was judged functionally andstructurally deficient by the Departmentsof Transportation of Ohio (ODOT) andWest Virginia (WVDOT), deciding toreplace it was an easy decision. Buthow best to design and construct it wasfar from an obvious choice, says DaveJeakle, lead engineer from the Tampaoffice of URS Corporation. Because itspanned the Ohio River between thetwo states, both states were involvedin the decisions—and created a uniquepartnership.The Ohio River at the bridge location lieswithin West Virginia’s boundaries. Sincethe bridge’s construction and trafficaffect both states, both the ODOT andWVDOT were involved. But rather thandivide the construction responsibilitybetween the two states, a uniqueprofilePomeroy-Mason Bridge / Pomeroy, Ohio to Mason, W.Va.ENGINEER OF RECORD: URS Corporation, Tampa, Fla.CONSTRUCTION ENGINEERING: Janssen & Spaans Engineering Inc., Indianapolis, Ind.CONSTRUCTION INSPECTION: Michael Baker Jr. Inc., Pittsburgh, Pa.PRIME CONTRACTOR: C.J. Mahan/National Engineering (a joint venture of C.J. Mahan Construction Co.,Grove City, Ohio, and National Engineering & Contracting Co., Westerville, Ohio)34 | ASPIRE, Summer 2008

A major consideration, especially forWest Virginia, was to minimize long-termmaintenance.Bridgeby Wayne A. Endicottarrangement for its construction wasreached.In this arrangement, the bridge is beingbuilt by the ODOT. On completion,ownership and responsibility formaintenance of the bridge will pass tothe WVDOT. Virtually all decisions on thebridge, such as its location and design,were hammered out between the twodepartments. The bridge is expected tobe completed this fall.“We evaluated several systems todetermine the best choice, with plentyof input from both states,” says Jeakle.“A major consideration, especially forWest Virginia, was to minimize longtermmaintenance.”Among the systems discussed werea simple tied arch; a three-span,continuous, parallel-chord steel truss;and a three-span, cast-in-place concretecable-stayed bridge. The cable-stayedoption was chosen, primarily becauseof the design’s aesthetics. “Althoughconstruction cost was definitely afactor in the decision-making process,when we compared all of the variousoptions, none stood out as being morecost efficient than another.” The finaldesign represents a consensus fromboth departments, including a varietyof officials, adds Michael Zwick, a seniorproject manager in URS’s Cincinnatioffice, who shepherded the project.75-Year Service LifeLongevity was another key factor inchoosing the concrete, cable-stayeddesign, says Zwick. “We project aminimum 75-year service life, providedthat certain routine maintenance tasksare performed. In that time, we wouldexpect that the stay cables will needto be replaced once and expansionjoints and bearings will need to bechanged twice. Also, the silica fumeconcrete overlay will need to be redoneapproximately every 20 years.”O ff i c i a l s a t t h e t w o h i g h w a ydepartments asked designers tostudy three different types of cablestayedbridges. The first type featureda single-tower, unsymmetrical designThe new Pomeroy-Mason Bridgebegins to take shape alongsideits predecessor at the right.The new bridge, over the OhioRiver between Pomeroy, Ohioand Mason, W.Va., is just 110 ftupstream from the functionallyobsolete steel structure it replacesto carry Ohio Route 33 over theOhio River. All photos: Bob Henry,Michael Baker Jr. Inc.Cast-in-place segmental cable-stayed bridge / West Virginia Department of Highways, Charleston,W.Va., OwnerSTAY-CABLE SUPPLIER: Dywidag-Systems International, Bolingbrook, Ill.BRIDGE DESCRIPTION: 1163-ft-long, three-span, symmetrical cable-stayed concrete bridge with a 675-ft-long center spanand two 244-ft-long side spansPOST-TENSIONING SUPPLIER: Dywidag-Systems International, Bolingbrook, Ill.BRIDGE CONSTRUCTION COST: $45.8 million (including approach spans)ASPIRE, Summer 2008 | 35

Concrete for the main span wasdelivered over the side spans andpumped into place.The design required a superstructureconsisting of concrete edge girders, 5-ft6-in. deep by 5 ft wide, with 1-ft 9-in.-wide transverse floor beams in eachsegment. The transverse beams eachcontain two 19-strand post-tensioningtendons. The 244-ft-long side spans andthe first 40 ft of the main span were caston falsework. Typical segment lengthsare 26-ft 6-in. long in the main span and17-ft 10-in. long in the side spans.Because the side spans are shorterthan desired for a cable-stayed bridge,it was necessary to add a significantamount of ballast in each side span toeliminate uplift and balance the longmain span, Zwick says. For this reason,the transverse floor beams in the sidespans are 9 ft thick to balance the mainspan’s weight.Construction proceedssimultaneously from both sidesof the Ohio River.Even then, there were more optionsto be considered, says Jeakle. Thefirst superstructure option featureda composite steel-grid system with anormal weight concrete deck in the two244-ft-long side spans and a lightweightconcrete deck in the main 675-ft-longcenter span. The second possibilityincluded normal weight concrete edgegirders and transverse floor beams.Although the lowest cost plan wasdeemed to be the symmetrical threespansystem with composite steel gridsuperstructure, the owners selectedthe system featuring concrete edgegirders. Officials at the WVDOT saidthat this system would require less longtermmaintenance, as it would not benecessary to periodically repaint thesteel structure.Two Identical TowersThe two delta-shaped towers aregeometrically identical. Tower foundationsconsist of a waterline footingsupported by six 8-ft-diameter drilledshafts. Ohio River water levels atthe bridge’s location can fluctuatesignificantly, Jeakle notes, with variationsfrom normal pool to 100-year floodstage varying by as much as 38 ft.For this reason, the footing caps wereshaped to create snag-free elements forvessels plying the river. The footing captapers from 30 ft wide at the top of theshafts to 16 ft wide at the bottom ofthe tower legs.Possible barge collisions are a concern,especially at the two towers. To addressthis, the tower legs below the bridgedeck are solid concrete, while thetower legs above the deck are hollowand contain the stay-cable dead-endanchorages. A fully post-tensioned crossstrut at deck level of each tower resiststhe tension force created through theangle change in the tower legs.ASPIRE, Summer 2008 | 37

The stay cables consist of 0.6-in.-diameter greased and sheathed strandswithin an ungrouted HDPE casing. Nonlinearviscous dampers are connected toall cables at deck level to minimize cablevibrations from wind and rain.The bridge provides an undividedroadway consisting of four 12-ft-widelanes. Also included are two 4-ft-wideshoulders and a 6-ft-wide sidewalk,creating a total width of approximately74 ft. The roadway alignment is on atangent for the bridge’s full length,except for a J-hook on the Ohio sideof the river. This 180-degree turn in theroadway, beginning approximately 150ft inland from the river bank, is madenecessary by the steep rocky hillside thatparallels the Ohio shoreline.The new bridge takesshape upstream from theexisting bridge, which remains open to traffic.The navigational channel of the river, onthe Ohio side, provides a minimum of645 ft of horizontal clearance and 55 ftof vertical clearance, which is consistentwith the clearances provided at otherOhio River bridges, Jeakle says.High Performance ConcreteThe cast-in-place concrete specificationfor the bridge’s superstructure called fora concrete mixture with a compressivestrength of 6000 psi and a lowpermeability of 1000 coulombs. The mixcontains fly ash and a high-range waterreducingadmixture. The 11-in.-thickdeck will be permanently protected byan overlay consisting of a silica fumeconcrete that meets the standard ODOTspecifications.When completed this fall, the bridgewill have white stay cables and all whiteconcrete surfaces, except the roadwaydeck, which will be painted with an offwhiteepoxy urethane.The bridge represents a spirit ofcooperation between governmentalbodies, which frequently can have theirown agendas, says Jeakle. “Probablythe biggest challenge in completingthis project was whether the two statescould come to a consensus on a designconcept agreeable to both. Whenit opens to traffic this fall, I believethat that question will be answeredpositively.”For more information on this or otherprojects, visit www.aspirebridge.org.BRIDGE 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.www.vsl.net • 888.489.268738 | ASPIRE, Summer 2008

Precast Span-by-SpanPrecast Balanced CantileverCast-in-Place Balanced CantileverIncremental Launchingpost-tensioningfor segmentalbridgesproviding– Tendons from4 to 37-0.6" strands– Form Travelers– Equipment– Installation Labor– Value EngineeringSMART HIGHWAY BRIDGEownercontractorpost-tensioningand form travelersVirginia DOTPCL Civil ConstructorsAVAR Construction Systems, Inc.Construction Systems, Inc.504-F Vandell WayCampbell, CA 95008408.370.2100info@avarconstruction.com

Bridge overSWINGLEY RIDGE ROADby Kevin Eisenbeis, Harrington & Cortelyou Inc.The bridge spans Swingley RidgeRoad and provides access to theparking garage.Cast-in-placeconcrete providesthe answerA cast-in-place concrete bridgeprovided the aesthetic solution whenSachs Properties Inc., owners of theChesterfield Ridge Center officedevelopment complex in Chesterfield,Mo., needed a bridge for access to theirnew parking structure and six-storybuilding. The complex site geometricscalled for a bridge to span SwingleyRidge Road, while also providing accessto the rooftop level of a new parkingstructure.A new, 322-ft-long bridge spanningSwingley Ridge Road was desired toallow easy access to Chesterfield RidgeCenter from the nearby North Outer40 parallel connector road and I-64. A100-ft-long upper level drive extension,projecting from the bridge, was alsoneeded for access to a new parkingstructure. A cast-in-place, reinforcedconcrete bridge, T-shaped in plan view,provided the elegant solution desired.The monolithic concrete structure,profileSwingley Ridge Road Bridge / Chesterfield, Mo.Bridge Designer: Harrington & Cortelyou Inc., Kansas City, Mo.Civil Engineer: Volz Inc., St. Louis, Mo.Geotechnical Engineer: Geotechnology Inc., St. Louis, Mo.Building Architect: Mackey Mitchell Associates, St. Louis, Mo.40 | ASPIRE, Summer 2008

A cast-in-placereinforced concretebridge provided theelegant solution needed.the main structure. Use of a monolithicconcrete slab bridge eliminatedstructural discontinuities and complexsuperstructure framing details wherethe elevated structure arms converged.Pier caps supporting girders were nolonger needed. Expansion joints on thestructure could also be eliminated, withjoints being used only at abutmentsand where the entrance drive joined theparking structure.Eric Neprud, project engineer forHarrington & Cortelyou, summarizedthe choice: “Selection of the voided slabbridge drastically simplified the detailingrequirements where the access drivemeets the main bridge.” The use of16-in.-diameter voids embedded withinthe 2-ft 3-in.-thick slab reduced weightand material requirements, allowing thethin superstructure to span up to 60 ftbetween pier support points. Drop panelsvarying from 6-in. to 10-in.-thick wererequired to distribute loads to the narrowcolumns. A 28-day concrete compressivestrength of 4000 psi was used with theMissouri Class B2 mix design, allowingthe bridge to carry AASHTO HS-20 liveloading. A 5-ft-wide sidewalk was alsocantilevered from the bridge.Chesterfield, located just west of St.Louis, Mo., is subject to CategoryB seismic requirements. The complexT-shape of the structure dictated thata three-dimensional analysis wouldbe required for seismic considerationswith a ground acceleration of 0.12g.Structural analysis utilizing a responsespectrum analysis with mTAB Stress (SAP386) software indicated displacementsand loadings would be acceptable.The tall, slender piers supported onsingle drilled shafts performed wellwhen analyzed for seismic loading.Conventional analysis of the bridge wasmade utilizing the Brass program.Field exploration consisted of fourborings extending through the 41-ft to46-ft-thick overburden and 25 ft intothe rock below. Due to the geology ofthe site, a potential for slope instabilityin the earth fill required special analysis.supported on single-column, “golftee” concrete piers, provided the idealsolution to meet all structural, thermal,seismic, geotechnical, and aestheticdesign requirements.Several structural options were initiallyconsidered for the bridge. Framing issuesand thermal movement requirementsfor steel and concrete girder spansproved to be undesirable where theupper level drive entrance connected toA T-shaped bridgeprovided the solutionfor all structural,thermal, seismic,geotechnical, andaesthetic designrequirements.Cast-in-place reinforced concrete / Sachs Properties Inc., St. Louis, Mo., OwnerBridge Contractor: St. Louis Bridge, St. Louis, Mo.Field Observation: Alper-Ladd, St. Louis, Mo.Bridge Description: A cast-in-place reinforced concrete bridge, T-shaped in plan view consisting of eight spanssupported on six columns and three end bentsASPIRE, Summer 2008 | 41

The site geometry called for a bridge to span the roadwayand provide access to the parking structure.The tall, slender piers supported on singledrilled shafts performed well when analyzed forseismic loading.Any change in natural conditions of thehighly plastic shaley clays could leadto instability. Drilled shaft foundationswere designed for an additional 40kips of lateral load, in addition to otherlateral loads on the piers, as a result ofpotential slope creep in the 45-ft-thicksoil mass overlying the limestonebedrock. Drilled shafts were socketed2.5 diameters into the limestone belowthe fill to provide additional lateralThe substructure consists of single pierson single drilled shafts.resistance. Since falsework and shoringwere used to build the new structure,recommendations were also providedfor allowable bearing pressures forfalsework support footings.The bridge was built over a 10-monthperiod. Following installation ofthe drilled shafts and pier columns,the voided slab superstructure wasconstructed on falsework with concreteplaced in a sequential manner. Positivemoment sections were placed first,followed by 30-ft-long segments overthe pier supports. Forms were camberedto account for dead load deflections andremoved when the concrete strengthreached 3000 psi.The cast-in-place concrete bridgeprovided an economical and attractivesolution in this combined commercialand residential setting while the complexgeometry of the site and shallowstructure requirements made the castin-placeoption ideally suited for thisapplication._____________________________Kevin Eisenbeis is a principal withHarrington & Cortelyou Inc., Kansas City,Mo.For more information on this or otherprojects, visit www.aspirebridge.org.AESTHETICSCOMMENTARYby Frederick GottemoellerThis structure is an excellent resolutionof a complicated structural andaesthetic problem: the bridge with abranch. Designing a bridge like this withtypical steel or concrete I-beams alwaysresults in a confusion of beam layoutsand awkward connections. The cast-inplacevoided slab, on the other hand,adapts readily. All of the connections andpoints of force transfer are inside theslab. The exterior shows only a smoothcontinuous surface along the main linesof the structure. The bridge seems to beall one piece. The eye effortlessly followsits edges from abutment to abutment.The cross section of the superstructurealso has enough torsional stiffnessto allow single column supports. Thisminimizes the number of columns andallows streets, planting areas, and viewsto flow through under the bridge. Thespace under the bridge remains a pleasantplace to be. Finally, the flares at thetop of the columns make clear the flowof forces from the superstructure to theground. They make this small but complexstructure memorable.42 | ASPIRE, Summer 2008

Spikes in Worldwide Steel Prices ImpactBridge ConstructionWorldwide demand and the weak dollar have led to unprecedentedprice increases and volatility for all types of steelproducts. According to data published by American MetalMarket (AMM), steel plate prices increased 63% between Januaryand May 2008; high-strength wire rod used in the productionof prestressing strand increased 34%, and steel reinforcementincreased 48%.These increases pose major challenges for owners, contractors,and industry suppliers. Out-of-date estimates can result infunding shortfalls. Fixed price bids, which have not anticipatedthese sky-rocketing prices, threaten the financial viability of contractorsand suppliers alike. Owners, contractors, and suppliersare urged to work together to meet this challenge and reasonablymanage risk for all involved in bridge construction.On a positive note, as material prices continue to rise, theuse of high-strength materials generally becomes more costcompetitive. Prestressed concrete bridges that proportionally049_DSI_ADUS_178x117 20.12.2006 11:06 Uhr Seite 1use less steel are even more economical when compared toother structural systems.Post-tensioning is being utilized on bridges in increasinglyvaried ways, including cable stays for long-span applications,segmental construction, on bridge decks, strengthening, andon spliced girders to extend the capabilities of precast elements.Post-tensioning offers some unique advantages, whichcan reduce material usage and improve overall economy andperformance.PTI has training programs to improve the quality of post-tensionedconstruction. The Bonded Post-Tensioning Certificationprogram is a comprehensive course on all aspects of bondedpost-tensioning installation. The 3-day training workshopis intended for construction personnel, inspectors, and constructionmanagers. Attendees are certified following successfulcompletion of the training and the subsequent examination.For more information about post-tensioned bridgesand training programs, contact PTI or visit our website at:www.post-tensioning.org.DYWIDAGPost-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, Summer 2008 | 43

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.hoodcanalbridge.comThis WSDOT site provides information about the HoodCanal Bridge Project on State Route 104. Click on“Construction cameras” to see work at the two off-siteconstruction locations, or visit the photo gallery for stillphotographs and the computer animation for time-lapsevideos and computer simulations.http://dot.ca.gov/dist1/d1projects/confusionhill/index.htmVisit this website for information about the South Fork EelRiver Bridges, also known as the Confusion Hill Bridges.www.fhwa.dot.gov/bridge/britab.htm.This FHWA website lists tables of frequently requestedNational Bridge Inventory (NBI) information. Data areavailable for several years as Excel or html files and in somecases as pdf files.http://www.wsdot.wa.gov/eesc/bridge/softwareGo to this website for a list of WSDOT Bridge EngineeringSoftware including PGSuper for the design and analysisof prestressed concrete superstructures.http://bridges.ci.stpaul.mn.usThis website provides information about bridges in the city ofSt. Paul, Minn. including bridge facts, construction projects,bridge maintenance, bridge clearance, and truck routes.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 49 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 National Research Information System provides abibliographic database of over 640,000 records of publishedresearch for all modes of disciplines and transportation.www.trb.org/CRP/NCHRP/NCHRPprojects.aspThis website provides a list of all National CooperativeHighway Research Projects (NCHRP) since 1989 and theircurrent status. Research Field 12—Bridges generally listsprojects related to bridges although projects related toconcrete materials performance may be listed in ResearchField 18—Concrete Materials. Some completed projectsare described below: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.http://trb.org/news/blurb_detail.asp?id=7443NCHRP Report 579, Application of LRFD Bridge DesignSpecifications to High-Strength Structural Concrete: ShearProvisions, examines research performed to extend theapplicability of shear design provisions for reinforcedand prestressed concrete structures in the AASHTO LRFDBridge Design Specifications to concrete compressivestrengths greater than 10 ksi.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 LRFD specifications language areavailable as online appendices.44 | ASPIRE, Summer 2008

S A F E T Y AND S E R V I C E A B I L I T YDurability of ConcreteSegmental Bridges by Brett H. Pielstick, Eisman & Russo Consulting EngineersWith the collapse of the I-35W bridge inMinneapolis last year, the durability of bridgeshas become a national issue. In a report 1sponsored by the American Segmental BridgeInstitute (ASBI), the durability of segmentalbridges is addressed in comparison to allstructure types listed on the National BridgeInventory (NBI). This article provides a summaryof the ASBI report.The information was based on the December2006 Federal Highway Administration (FHWA)NBI data base, which docu mented the conditionof 597,479 bridges in the United States. Themajority of these bridges were constructedduring two bridge-building booms—oneduring the post-depression era and the secondduring the interstate construction boom. Manyof these bridges are, therefore, 40 to 70 yearsold and are begin ning to show their age, with73,798 bridges (12.4%) rated as structurallydeficient. An additional 80,317 bridges arelisted as functionally obsolete. The discussionin this article focuses exclusively on structurallydeficient bridges.Figure 1 shows the proportion of bridges bymaterial type compared to Figure 2, which showsthe proportion, by type, for structurally deficientbridges. A discussion of structurally deficientbridges was provided in ASPIRE, Winter 2008.The pur pose of the ASBI durability report isto assess the condition of concrete segmentalbridges, with service lives approaching 40 yearsin the United States, along with their ability toprovide long-lasting structures.In Figure 1, the categories of steel bridgesrepresent about 32% of the overall bridges inthe FHWA survey, 2 but they are responsible forSteelContinuous8.2%Prestressed ConcreteContinuous 3.3%PrestressedConcrete 18.3%Steel 23.5%Masonry 0.3%Wood4.6%ConcreteContinuous13%Concrete28.4%FIGURE 1Proportion of bridges by material type.Aluminum Iron 0.2%Other 0.1%about 54% of the structurally deficient bridgesas shown in Figure 2. Reinforced, prestressed,and post-tensioned concrete bridges represent63% of the overall bridges but only represent32% of the structurally deficient bridges,with 6% of the prestressed con crete bridgesand 0% of the segmental bridges classified asstructurally deficient. This means that the ratioof structurally deficient bridges to the totalnumber of bridges is 5.8 times greater for steelbridges than for prestressed concrete bridges and2.7 times greater for concrete bridges. Timberbridges, while repre senting only 4% of the entirenumber of structures, represent 14% of thestructurally deficient bridges.The most frequent reason that steel and timberbridges are clas sified as structurally deficient is alow structural adequacy rating. This means thebridge has a lower load-carrying capacity.The information for the ASBI survey identifiedover 400 segmental bridges with 275 inspectionreports and condition ratings obtained. Allsegmental bridges were rated as “fair” or better.Of the 273 bridges, over 97% had superstructureSteelContinuous5.9%PrestressedConcrete 5.8%PrestressedConcrete Continuous0.5%Steel 47.6%Wood13.8%Masonry 0.6%Aluminum Iron0.3%Concrete18.7%ConcreteContinuous6.7%Other 0.1%FIGURE 2Proportion of structurally deficient bridges bymaterial type.ratings of “satisfactory” or better, 85% hadsuperstructure ratings of “good” or better and 25%had superstructure ratings of “very good” or better.On average, the 275 segmental bridges, built overthe last 35 years, with inspection data gatheredaveraged a superstructure rating of “good.”The NBI inspec tion data 2 summarized in theASBI report shows that concrete bridges continueto perform well. No structural deficiencies insegmental concrete bridges were noted. Otherbridges constructed during the past 35 yearsusing other materials have expe rienced varyinglevels of structural deficiency.REFERENCES1. Pielstick, Brett, Durability Survey ofSegmental Concrete Bridges, Third Edition,September 2007, available from ASBI.2. Ann Shemaka, FHWA Bridge Technology“Tables of Frequently Requested NBIInformation,” updated May 1, 2007, at http://www.fhwa.dot.gov/bridge/britab.htm.ASPIRE, Summer 2008 | 45

STATEConcrete Bridges inWashingtonStateby Jugesh Kapur and DeWayne Wilson, Washington State Department of TransportationThe Selah Creek Fred G. Redmond Bridges on I-82 near Yakima opened in 1971.Concrete is the material of choice forthe majority of bridges in the State ofWashington. Approximately 2600 out of 3000bridges maintained by the Washington StateDepartment of Transportation (WSDOT) have amain span type that consists of concrete. The oldestof these bridges dates back to the early 1900s.The first known use of a precast, prestressedconcrete girder bridge in Washington was in 1954for a bridge over the Klickitat River on State Route142. The center span of this three-span bridge is90 ft and consists of four precast segments about22 ft in length that were supported on falseworkin place and then post-tensioned together. Thecontractor chose to install the girder in units,based on the lifting capacity of his crane.Technology and equipment have advanced sincethen to allow current bridges with spliced girdersto have lengths in excess of 200 ft.There are two major statewide transportationimprovement programs underway. The first,known as the “Nickel” funding package, began in2003 with a total budget of $3.9 billion to addressprimarily congestion and safety on 158 projects.The second, known as the “TransportationPartnership Account” began in 2005 with a totalbudget of $7.1 billion to address preservation andmobility on 274 projects. Concrete bridges willplay a big part in these new programs.Selah Creek ArchesThe twin Selah Creek Fred G. RedmondBridges on I-82 provide a connection south fromEllensburg to Yakima. They were the largest archspan bridges in the United States at 549.5 ft whenthey opened to traffic in 1971. The top of the archspan is 325 ft above the canyon and requiredfalsework to be built from the valley below. Thesuperstructure on each bridge consists of 17 spansof prestressed concrete girders that are 78.5 ftlong. These two bridges are examples of the useof concrete for nearly 780 interstate bridges builtbetween 1955 and 1975 that are now 30 to over50 years old.South 317th St HOV AccessIn 2006, a bridge was opened over I-5 nearFederal Way to provide direct access for busesand high occupancy vehicles from I-5. Bridgeengineers decided to use precast, prestressedconcrete trapezoidal tub girders 5 ft wideand 6 ft deep that were spliced together withpost-tensioning. The bridge span is curved atthe intersection with the access ramps toaccommodate turning buses. The structure is 128ft long with four spliced precast, trapezoidal tubgirders, each consisting of 35-ft- and 88-ft-longsegments. The segments were temporarilysupported on falsework and then post-tensionedtogether. The bridge has 50-ft radius curvesconnecting to the ramp side. Curved edge beamsframe into the diaphragm at a splice locationand are supported on an abutment wall at thepier. This configuration of straight precast girderswith curved edge beams is typically achieved withcast-in-place box girders. Trapezoidal girderswere added to the WSDOT standards in 2004.Precast trapezoidal tub girder.46 | ASPIRE, Summer 2008

The Methow River Bridge usesWSDOT’s “Super Girder.”These girders have span lengths up to 140 ft, areconsidered for special bridge projects that need alow profile, and have been used in nine WSDOTbridges to date.Transporting WSDOT’s “Super Girder.Methow RiverThe Methow River Bridge on State Route 20in Okanogan County replaced a seven-spanconcrete T-beam bridge built in 1931. The oldbridge had span lengths of 53 ft with severalpiers in the river. The new bridge, completed inSeptember 2003, has two 180.5-ft-long spansthat are 35 ft wide curb-to-curb with a totallength of 360.8 ft. The bridge uses seven linesof 82.7-in.-deep precast, prestressed concreteWSDOT W83G “Super Girders” on 6.1 ft centerssupporting a 7.9-in.-thick cast-in-place concretedeck. WSDOT introduced these deeper girders,commonly called “Super Girders” in 1999. TheMethow River Bridge was their first application.There are three sizes of these girders designatedWF74G, W83G, and W95G with the numberequating to the approximate girder depth ininches. These “Super Girders” are capable ofachieving span lengths up to 185 ft, based ona 200,000 lb weight limit for transporting thegirders to the construction site. To date, WSDOThas used the W83G girders for eight bridges withthe longest girder length being 180.75 ft.The length and weight of the girders installedat Methow River required special planning forthe 250-mile trip from the precasting plantin Tacoma. This trip took 9 to 13 hours. Theintroduction of new high performance concrete(HPC) mix designs allowed WSDOT bridgedesigners to develop these new “Super Girder”sizes. The Methow River girders used a specified28-day concrete compressive strength of 10,000psi with actual strengths ranging from 10,600psi to 15,200 psi. The concrete mix proportionsincluded 752 pcy of Type III cement and 50 pcyof silica fume, placed with a water-cementitiousmaterials ratio of 0.27.The SR 502 bridge over I-5 near Vancouver uses W83Gs with a girder length of 176 ft.Twisp RiverThe Twisp River Bridge is also on StateRoute 20 less than 1 mile from the MethowRiver Bridge and is located in the town of Twisp.The new bridge was completed in 2001 andreplaced a four-span, cast-in-place concreteT-beam bridge built in 1935. The Twisp andMethow Rivers are home to several endangeredfish species. Environmental permit conditionslimited the amount of time for constructionbelow the normal high water mark duringthe months of July and August. WSDOTbridge engineers decided to use a new precast,prestressed concrete W95PTMG single-spanASPIRE, Summer 2008 | 47

girder that would be fabricated and deliveredin three units, erected on temporary falseworkbents, and post-tensioned together once the deckwas placed. The span length is 197 ft and thegirders are 7.9 ft deep. The girders used HPC witha 28-day compressive strength of 8000 psi. Allpost-tensioned anchorages were placed in a castin-placeconcrete end diaphragm. At the time,this was the longest precast, spliced concretegirder in WSDOT’s inventory. This type of “SuperGirder” was developed in 1996 through a jointeffort between WSDOT and the Washington stateprecast, prestressed concrete industry.The Twisp River Bridge spliced “Super Girder.”Hood Canal Floating BridgeThe Hood Canal Bridge is the longest concretefloating bridge in the world over a saltwatertidal basin. The basin is up to 340 ft deep witha maximum tidal swing of 16.5 ft. On average,15,000 cars per day use this bridge, whichprovides a vital link to the northern part of theOlympic Peninsula. The bridge was originallybuilt in 1961. The west half sunk during a stormin 1979 and was replaced in 1982. WSDOTis currently in the middle of a $478 millionrehabilitation project to replace the east halffloating section along with both approaches,install new concrete floating anchors, and widenthe west half superstructure. The project beganin 2003 and is now about 73% complete. Furtherdetails of the bridge are provided in the articlebeginning on Page 16.WSDOT also owns and maintains three otherconcrete floating bridges, the Evergreen PointBridge on State Route 520, which is the world’slongest, and the Homer Hadley and Lacey V.Murrow Bridges on I-90.PGSuper Computer ProgramWSDOT has developed an in-house computerprogram for engineers to design precast,prestressed concrete girders. It is availablethrough a free download. (See ConcreteConnections on Page 44 for details.) PGSuperis our precast, prestressed concrete girder designand analysis software. It can be used to designand to check designs in accordance with theAASHTO LRFD Bridge Design Specification andWSDOT criteria. The flexural design featurecomputes the number and configurationof prestressing strands and the minimumrequired concrete release strength. The sheardesign feature determines the number, size,and spacing of transverse reinforcement forvertical shear, horizontal shear, bursting, andstrand confinement. Specification checkingevaluates girders for compliance with strength,serviceability, and detailing criteria. Girdersare evaluated for stresses and stability duringhandling and transportation. Temporaryprestressing to control camber, improve stability,and reduce concrete release strengths may alsobe input. The program has been designed toallow for future expansion and updating asdesign criteria and user expectations change.______________________Jugesh Kapur is bridge and structures engineerand DeWayne Wilson is bridge managementengineer with the Washington State Department ofTransportation.For more information on Washington Statebridges, visit www.wsdot.wa.gov/eesc/bridge.Prestress girders rolled into position on the Hood Canal Bridge approaches.Hood Canal floating bridge.48 | ASPIRE, Summer 2008

American Coal Ash AssociationThe Romans used volcanic ash to build structures that we admire over 2000 years later. Engineers today can achieve the same high-strengthendurance using coal combustion products (CCPs)—materials produced when we burn coal to generate electricity.Though the material properties vary according to coal composition and power plant operating conditions, experts can advise on quality anddetermine the best mix design for almost any condition and project. Mix designs exceeding 40% fly ash have proven successful in many projects.Experts with first-hand experience may be located by contacting the American Coal Ash Association, an industry association devoted toeducating designers, engineers, concrete professionals, regulatory officials, and others about CCPs’ technical, environmental, and commercialadvantages.Fly ash concrete has been specified because of its high strength and durability for the John James AudubonBridge near Baton Rouge, La. When complete, it will be longest cable-stayed bridge in North America.The California Department of Transportation (Caltrans), a leader in fly ash concrete projects, requiredhigh volume fly ash mixes for the largest bridge project in its history—the San Francisco-Oakland BayBridge. Using innovative specifications and blending techniques, Caltrans was able to improve the workability,hardening, and permeability properties of the bridge’s concrete. A number of engineering standards andspecifications define CCP applications, thus ensuring high quality performance and products.In addition to a myriad of core performance attributes in construction and industry, CCPs use can conserve natural resources, reducegreenhouse gas emissions, and eliminate the need for additional landfill space. For more information, contact ACAA at info@acaa-usa.org orcall 720-870-7897.TAKING THE LOAD OFF…Bridges Around the WorldGeorge P. Coleman Memorial Bridge - VirginiaLightweight concrete deck on widened replacementtrusses.EconomicalSolutions forRehabilitating Bridges– Proven Enhanced Durability– Reduced Deck Weight Increases Rating– Use Wider Deck on Same Structure– Reduced Weight for Precast Elements– Reduced Seismic and Foundation Loads– Consistent Quality and Properties– Easy Pumping and Placement– Shipped anywhere in the US and World!Mattaponi River Bridge - VirginiaLightweight concrete deck andlong-span spliced girders.HIGH PERFORMANCE LIGHTWEIGHT AGGREGATE800.898.3772 704.637.1515www.stalite.com10857_Carolina_Stalite_Company_fall07.indd 18/23/07 10:00:30 AMASPIRE, Summer 2008 | 49

CITYIn the wake of tragedy,more funding helps expand bridge programSt. Paul CreatesThe Raspberry Island Bridge features five spans of cast-in-placeconcrete slab girders. The bridge ties in with the nearbyHariett Island trail system and the River Walk, andfeatures “St. Paul Rail” designed hand rails.Replacement Plan by Kevin L. Nelson, City of St. Paul, Minn.The collapse of the I-35W bridge in theTwin Cities region brought increasedattention to the condition of Minnesota’s bridgeinfrastructure, beginning a process to increasethe available funding for replacement projectsand rehabilitation. Most of our recent bridgeand retaining wall projects have been concretestructures, and we expect that will continue forthe future.The additional funding, especially throughthe state matching-funds program, is a welcomeaddition. It is being financed by a bond fundsupported by an increase in the gasoline tax—the first such increase in 25 years. Minnesotahad fallen behind other states in increasingthis funding as there was no way to include aninflation factor in our budgeting. This caused usto fall behind in our construction. This programwill help us to catch up and update bridges morequickly.In all, the city has 331 bridges within theright-of-way of the city, county, and statewith 110 of those being concrete. The City ofSt. Paul has 12 structurally deficient bridges,according to our current bridge inventory. All areprogrammed for replacement in the next 5 years,with three to be replaced in 2008. The city alsohas nine Mississippi River crossings, includingthree concrete arch bridges and a segmental boxgirder bridge. All have been rebuilt or constructednew within the past 15 years.When we replace or build a new bridge, mostoften, we use the standard Minnesota Departmentof Transportation precast, prestressed concreteI-girders, although the state recently developednew standards that include a solid box beamdesign and an inverted T-beam. We have not yetdesigned with those components, but we will beusing them once we see how best to apply them.Cast-in-place concrete decks are used on most ofthe bridges.We use concrete on our new bridges todaybecause it fits our needs. It is a versatilematerial, providing a variety of ways that wecan mold it and color it. It is economical andreadily available. It also offers high durabilityand strength that will provide a service life of 50to 100 years.Two of the three bridges being replaced thisyear will be replaced with concrete bridges. Weanticipate replacing the remaining deficientbridges at a rate of two bridges per year. Mostof these are local roads crossing railroads, andsome of them are as much as 100 years old. Thebridges being replaced this year were constructedin the 1950s.One of our most notable recent bridges was theRaspberry Island Bridge, which is the only landlink to the island for vehicles and pedestrians.The five-span, cast-in-place concrete slab bridgewas built during a difficult spring flood, whichslowed falsework and forming procedures. Thebridge features two 50-ft-long end spans andthree 75-ft-long center spans. Ornamental steelrailings and a colored concrete overlay on thedeck panels were used to add visual appeal tothe bridge.City engineers work closely with the state onachieving design goals and coordinating workso that designs are complementary, efficient, andcost-effective. Concrete designs ensure that thosegoals are met for us.The Earl Street Bridge is a multi-span design featuringprecast concrete beams that replaces a deteriorated structureon the site. The railings feature the St. Paul StandardOrnamental rail and Lantern style lighting._____________________Kevin L. Nelson, P.E., is the bridge division managerfor the Public Works Department of the City of St.Paul, Minn.Editor’s NoteIf your city has a high percentage of concretebridges or some interesting and innovativeconcrete bridges and would like to be featuredin ASPIRE, please let us know at info@aspirebridge.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, Summer 2008 | 51

AASHTO LRFD2008Interim Changes Part 2by Dr. Dennis R. MertzSix agenda items related to concrete structures were adopted by the AASHTO Subcommittee onBridges and Structures (SCOBS) in Wilmington, Delaware, in July 2007. Agenda Items 32 through37 were developed by Technical Committee T-10, Concrete Design, over the past several years and movedto the full subcommittee ballot last year. The agenda items represent revisions and additions to theAASHTO LRFD Bridge Design Specifications or the AASHTO LRFD Bridge Construction Specificationsand appeared as the 2008 Interim Revisions published earlier this year. Agenda items 32 through 34were discussed in the Winter 2008 issue of ASPIRE. The other three 2007 concrete-structures agendaitems are reviewed in this article.Agenda Item 35 is a relatively straightforwarditem addressing issues regardingcombined shear and torsion. It corrects errorsin equation numbering in Articles 5.8.6.5 andC5.8.6.5, Nominal Shear Resistance, and addscommentary on the use of Equation 5. Thisequation is only used to establish concretesection dimensions for sections subjected tocombined shear and torsion.Agenda Item 36 is a companion to a2007 agenda item moved forward by TechnicalCommittee T-5, Loads and Load Distribution,which simplified the determination of effectiveflange width in Article 4.6.2.6 in Section 4,Structural Analysis and Evaluation. The revisionto the effective flange width determination isapplicable to sections of all materials and thus isincluded in the general section on analysis. Therevision of Article 4.6.2.6 states that in general“the effective flange width of a concrete deck slabin composite or monolithic construction may betaken as the tributary width perpendicular to theaxis of the member for determining cross-sectionstiffnesses for analysis and for determiningflexural resistances.” There are exceptions tothis simplification specified in Article 4.6.2.6including girders with large skew angles.Agenda Item 36 standardizes the definition of“b” in Articles 5.3, 5.7.3.1.1, and 5.7.3.2.2, bydefining it as the width of the compression faceof the member, or for a member with a flangein compression, effective width of the flange asspecified in Article 4.6.2.6.Agenda Item 37 clarifies Article 5.10.6.3with regard to column ties for bundled bars.This clarification is made by modifying everyreference to “bars” in the fourth paragraph ofArticle 5.10.6.3 to “bars or bundle.” The existingspecification language was not fully clear andrequired interpretation as to how bundled barsshould be treated. Making the requirementsexplicit eliminates the need for designerinterpretation, and provides more consistentapplication of the specifications to columns withbundled bars.The SCOBS met in Omaha during May andadopted changes for publication in 2009. Theseadditions and revisions will be reviewed anddiscussed in future articles.52 | ASPIRE, Summer 2008

Integrated 3D DesignParaBridge is a parametric 3D bridge modeling anddesign system that puts powerful and flexible bridge generation,geometry, and design tools at your fingertips.Designed and created within the state-of-the-art Microsoft.NET Framework, it represents the future of integrated 3Dbridge engineering.Laying out a bridge has never been easier. Powerful modelingwizards help you rapidly import or enter bridge alignmentand roadway data. Girder and pier framing tools giveyou a highly-leverage means of describing the bridge layout.Piers and girders of multiple types can then be insertedinto the project—all parametrically.ParaBridge All pertinent bridge geometry is solved by ParaBridge:deck elevations, girder lengths, bearing data, quantities,etc. Element design is smooth and seamless. BothPSBeam and ETPier are tightly integrated withParaBridge.The main view is a true 3D object-oriented model of yourbridge. Zoom, rotate, and pan the model in real time.ParaBridge utilizes technically advanced OpenGL graphicswith no third party add-ins. The result: a high-performancesystem with no need to purchase an expensive CADsystem to run it. Yet the model can be seamlessly passedto CAD software as needed.PSBeam PSBeam V3 is a high-performanceprogram for the design andanalysis of simple-span orcontinuous precast, pretensioned or post-tensionedconcrete bridge girders. PSBeam is the software ofchoice for many bridge engineers who demand flexibility,high performance, and rock-solid reliability.Virtually any precast beam type and pretensioningpattern can be handled by PSBeam. You can evenextend spans using spliced girder technology.PSBeam can accommodate the needs of allstakeholders in the life of a girder—from design tofabrication, through to load rating.LRFD.comETPier ETPier seamlessly combines thefunctionality of a state-of-the-artstructural analysis engine withconcrete column, beam, and footing design. Integrationof these critical design tasks into one system means youget superior productivity and flexibility with improvedquality control.ETPier is specifically designed for bridge substructures.Powerful parametric modeling wizards are included tofacilitate rapid structure layout and generation. Specifywhich load combinations to investigate and ETPier willautomatically process them and quickly identify thegoverning case for each component of the structure.Erikssontechnologies© 2008 Eriksson Technologies, Inc.

XHood canal Bridge / WASHINGTONNEW TRANSITIONSPANThe 20 anchors builtfor the East half are29 ft tall and rangein diameter from 46 ftto 60 ft.Hood CanalBridge pontoonconstruction cycles.Hood Canal Bridge Pontoon Construction CyclesNEW DRAWSPAN ASSEMBLY PONTOONS RETROFITTED ROADWAY PONTOONS NEW ROADWAY PONTOONSZD NA YD YFPAWVUTSRQWEST-HALFDRAW SPANFIRST CYCLE (PA, PB, Q)......................... Completed: December 2006SECOND CYCLE (NA, NB, YD, YE, YF).... Completed: July 2007ZCNBYE PBRETROFITTING (R, S, T) .......................... Completed: September 2007THIRD CYCLE (ZC, ZD, V, X) .................... Completion: February 2008Source: WSDOT Hood Canal Bridge Project OfficeFORTH CYCLE (U, W)............................... Scheduled Completion: September 2008

hood canal Bridge / WASHINGTONOnce the pontoons are joined intosubassemblies of multiple pontoons,the elevated roadway is constructedon top of the floating pontoonfoundations. The roadway decktowers over the top of the pontoondecks as high as 52 ft near theeastern shoreline.ASPIRE, Summer 2008 | Web

I-10 Bridge Replacement / floridaPrecast concrete seal slab with side formsfor the channel pier footingsPhoto: Charles Rudie, PB.

I-10 Bridge Replacement / floridaPrecast pile footings with reinforcement cagesin the piles reduced the amount of cast-inplaceconcrete construction over water.Photo: Charles Rudie, PB.ASPIRE, Summer 2008 | Web

I-10 Bridge Replacement / floridaPrecast concrete pile caps were used witha cast-in-place connections.Photo: Charles Rudie, PB.Web | ASPIRE, Summer 2008

I-10 Bridge Replacement / floridaTypical pier configuration.Photo: Charles Rudie, PB.ASPIRE, Summer 2008 | Web

I-10 Bridge Replacement / floridaThe first of the twin bridges wascompleted in 20 months.Photo: Charles Rudie, PB.Web | ASPIRE, Summer 2008

I-10 Bridge Replacement / floridaLow-level pile bents.Photo: Charles Rudie, PB.ASPIRE, Summer 2008 | Web

Photo: ©Caltrans.South fork eel river Bridges / california

South fork eel river Bridges / californiaSection near base of pier forthe south bridge. Cornerelements of the hollow pierare heavily confined withwelded hoops to achievegood ductility during aseismic eventPhoto: ©Caltrans.ASPIRE, Summer 2008 | Web

Photo: ©Caltrans.Web | ASPIRE, Summer 2008

Photo: Michael Baker Jr. Inc.Pomeroy-Mason Bridge / WEST VIRGInia

Pomeroy-Mason Bridge / WEST VIRGIniaPhoto: Michael Baker Jr. Inc.ASPIRE, Summer 2008 | Web

Pomeroy-Mason Bridge / WEST VIRGIniaPhoto: Michael Baker Jr. Inc.Web | ASPIRE, Summer 2008

Pomeroy-Mason Bridge / WEST VIRGIniaPhoto: Michael Baker Jr. Inc.ASPIRE, Summer 2008 | Web