historic context of maryland highway bridges built between 1948 ...

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SECTIONFOURPost World War II Technological DevelopmentsThese advancements greatly improved metal truss bridge building economy (Bigelow 1975: 242-243). As a rule, however, truss bridges are only rarely built today.5.3.2 Metal Girder Bridges1948-1960: 468 metal girder bridges constructed (Maryland State Highway Administration2003).Following the close of World War II metal girder bridge technology was adopted by countiesand municipalities across the United States. From 1920-1965, metal girder bridges and bridgesupport structures were constructed using metal I-beams and metal plate girders. These bridgescommonly featured I-beams and plate girders that were encased in concrete.After World War II, aluminum and other alternative metals were occasionally utilized by bridgebuilders. In Maryland, an aluminum girder bridge (Bridge # 13046) was constructed over thePatapsco River‘s South Branch near Sykesville in 1963. This bridge was constructed by the StateRoads Commission and International Aluminum Structures Inc.Bridge #13046 is the only bridge of its type in Maryland and one of only seven in NorthAmerica. Bridge #13046 is a three-span structure made of riveted and triangular box stiffenedsheet girders. These members support a light concrete slab sheathed with a bituminous deck thatserves as the riding surface (Spero and Berger & Associates 1995: 109-112).5.3.3 Metal Suspension Bridges1948-1960: 1 metal suspension bridge project completed (Maryland State HighwayAdministration 2003).The best example of a metal suspension bridge in Maryland is the wire cable strung, ChesapeakeBay Bridge (Spero and Berger & Associates 1995: 114-118), completed in 1952. Due to the factthat these long spanning bridges rely on a roadway suspended from cables, these bridge typesmust be aerodynamically stable. An infamous aerodynamically unstable bridge is the TacomaNarrows Bridge in the State of Washington. This bridge is well known for its convulsions in theface of high winds (Matsuo Bridge Company 1999).5.3.4 Steel Arch Bridges1948-1960: 3 steel arch bridges constructed (Maryland State Highway Administration 2003).Steel arch bridges were usually constructed to span long distances, such as wide river corridors.Examples elsewhere in the US include the Hell Gate Bridge in New York, New York; the HenryHudson Bridge over the Hudson River in New York, New York; and the Rainbow Bridge atNiagara Falls (Hollingsworth 1975: 89-94). The construction of these spans has slowed since theadvent of the cable-stayed bridge (National Information Service for Earthquake Engineering2004).Steel arch bridge construction benefited from the many technological innovations that wereadopted during the postwar period. Innovations that benefited this type of bridge constructionincluded; improvements in steel quality, strength and corrosion resistance, planning, planstandardization and prefabrication of structural elements, the incorporation of bolt technology\15-SEP-11\\ 5-4
SECTIONFOURPost World War II Technological Developmentsand improvements in welding techniques. These developments economized and enabled anincrease in the efficiency of construction of these bridge types (Hollingsworth 1975: 87-89).5.3.5 Movable Bridges1948-1960: 5 movable bridges constructed (Maryland State Highway Administration 2003).Movable bridges are put in place to fit unique situations where static span bridges would impedethe movement of objects in the waterways below the span. Vertical lift and bascule bridges arethe most frequently constructed types (Suffness 1992: 4, 11). The replacement Woodrow WilsonBridge Project, a bascule bridge, is currently underway between the States of Maryland andVirginia. This bridge links the two states, carries I-95/I-495 and spans the Potomac River(Woodrow Wilson Bridge Project: Project Overview: What and Why 2004).Many technological improvements refined movable bridge construction between the years of1924-1974. Many patented designs became available after the expiration of their owner‘s patentsin the 1940s and 1950s. Plan standardization economized fabrication. The abandonment ofriveting and the adoption of welding, use of new metal types and alloys, gearing efficiencyimprovements and improvements in bearings, lubrication and efficiency all played a vital role inthe development of this bridge type. Additionally, electrical power was incorporated into bridgemovement devices and later, remote controls of these electrical devices were adopted into thecontrol mechanisms of these bridges (Hardesty, Fischer and Christie 1975: 520, 522).5.3.6 Prestressed Concrete Bridges(See below for bridge counts.)The development of prestressed concrete broadened the use of concrete in bridge constructionnationwide (Spero and Berger & Associates 1995: 138). In 1955, the Bureau of Public Roadspublished the Criteria for Prestressed Concrete Bridges. This publication further encouragednationwide adoption of the technology (Spero and Berger & Associates 1995: 138). The WalnutStreet Bridge, in Philadelphia, Pennsylvania, which utilized post-tensioned construction in 1949,was a notable and unusual exception. Post-tensioning was much more common in Europe thanNorth America in the material‘s early years due to German and English strides in materialdevelopment (Lin and Kulka 1975: 496, 491).The development of prestressed concrete is directly related to the development of high-strengthsteel. Prestressed concrete can be created in two ways: it can be accomplished via pretensioning,in which the concrete is cast around steel cables that are already in tension; or the concrete canbe post-tensioned. In post-tensioning, concrete is poured with intentional voids that allow for thethreading, stretching, and anchoring of cables after the concrete has hardened. Both means areutilized in bridge construction—the former are elements that are precast in the factory; the latterfor the casting and later tensioning of members in place (Lin and Kulka 1975: 491-495).Within the United States, precast structural components were most commonly used inprestressed bridge construction. The precasting process was economical because it allowedstructural members to be fabricated off-site and for the member forms to be re-used. Themembers, if not cast on-site, needed to be transported via road or rail to the bridge constructionsite. Forms were also used in place at the construction site and it was possible for an entire span\15-SEP-11\\ 5-5
Page 3 and 4: F I N A L R E P O R THISTORIC CONTE
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Page 10 and 11: Table of ContentsConclusion and Rec
Page 12 and 13: SECTIONONEIntroductionTwenty one br
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Page 18 and 19: SECTIONTHREEHistoric Context1960 on
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Page 36 and 37: SECTIONFOURPost World War II Techno
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Page 42 and 43: SECTIONFIVEConsulting Engineers and
Page 48 and 49: SECTIONSIXResults of Field Investig
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SECTIONSIXResults of Field Investig
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SECTIONSEVENConclusion and Recommen
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SECTIONEIGHTReferences CitedCorddry
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SECTIONEIGHTReferences CitedKaszyns
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SECTIONEIGHTReferences CitedSeely,
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Appendix A1948-1960 Maryland Bridge
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Appendix BMaryland Bridges By Type
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Appendix CResumes of Key Personnel\
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Appendix DNotes From August 25, 200
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Appendix DNotes From August 25, 200
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