A continuous truss bridge is a truss bridge that extends without hinges or joints across three or more supports. A continuous truss bridge may use less material than a series of simple trusses because a continuous truss distributes live loads across all the spans; in a series of simple trusses, each truss must be capable of supporting the entire load.
26-718: The Milton–Madison Bridge (also known as the Harrison Street Bridge) is a continuous truss bridge that connects Milton, Kentucky and Madison, Indiana . It carries approximately 10,000 cars a day. This bridge is the only vehicular crossing of the Ohio River for 26 miles (42 km) going upstream (the Markland Bridge near Vevay, Indiana ) and 32 miles (51 km) downstream (the Lewis and Clark Bridge in northeast Louisville ). The bridge provides
52-664: A cantilever bridge. The Forth Bridge is a notable example of an early cantilever bridge. This bridge held the record for longest span in the world for twenty-nine years until it was surpassed by the Quebec Bridge . The engineers responsible for the bridge, Sir Benjamin Baker and Sir John Fowler , demonstrated the structural principles of the suspended span cantilever by sitting in chairs and supporting their colleague, Kaichi Watanabe , in between them, using just their arms and wooden poles. The suspended span, where Watanabe sits,
78-507: A hinge in the girder. Heinrich Gerber was one of the engineers to obtain a patent for a hinged girder (1866) and is recognized as the first to build one. The Hassfurt Bridge over the Main river in Germany with a central span of 124 feet (38 metres) was completed in 1867 and is recognized as the first modern cantilever bridge. The High Bridge of Kentucky by C. Shaler Smith (1877),
104-496: A more comprehensive worldwide list, see [1] : Cantilever bridges A cantilever bridge is a bridge built using structures that project horizontally into space, supported on only one end (called cantilevers ). For small footbridges , the cantilevers may be simple beams ; however, large cantilever bridges designed to handle road or rail traffic use trusses built from structural steel , or box girders built from prestressed concrete . The steel truss cantilever bridge
130-566: A partnership with the Kentucky Transportation Cabinet (KYTC), designed a new bridge to replace the original bridge. The new project was headed mostly by INDOT. The original bridge was removed except for several piers in the waterway, which were rehabilitated and widened to accommodate a new, wider steel-truss superstructure. Scour mitigation was also performed on the existing piers. The new bridge also features an ADA -compliant pedestrian walkway. Construction for
156-483: A pedestrian sidewalk opened that October. This two lane vehicular bridge is the Ohio River crossing for U.S. Route 421 . The bridge has a main span of 600 feet (180 m) and total length of 3,184.2 feet (970.5 m). The original bridge had a deck width of a mere 20 feet (6.1 m), and above the deck the vertical clearance was 16.8 feet (5.1 m). Built by J.G. White Engineering Corp., construction
182-508: A single continuous truss bridge. Continuous truss bridges started to be constructed in Europe during the second half of the 19th century. Although the advantages of continuous bridges were known, three main engineering challenges slowed their widespread adoption: However, it was possible to avoid these issues to a certain extent through careful design. The early European bridges were usually lattice trusses with three to five spans. An example
208-418: A sufficiency rating of 33 out of a possible 100; its superstructure condition rating was considered "poor". Modern trucks were unable to safely use the old bridge. The new bridge has a 40-foot (12 m)-wide road bed, plus a 5-foot (1.5 m) cantilevered pedestrian-only path. Bicyclists are banned from the sidewalk, but may use the new bridge's 8-foot (2.4 m) shoulders. A Milton–Madison bridge study
234-505: Is formed by two cantilever arms extending from opposite sides of an obstacle to be crossed, meeting at the center. In a common variant, the suspended span , the cantilever arms do not meet in the center; instead, they support a central truss bridge which rests on the ends of the cantilever arms. The suspended span may be built off-site and lifted into place, or constructed in place using special travelling supports. A common way to construct steel truss and prestressed concrete cantilever spans
260-424: Is in the center. The wooden poles resist the compression of the lower chord , while the outstretched arms support the tension of the upper chord. The placement of the brick counterweights demonstrates the action of the outer foundations. Cantilever Bridge.—A structure at least one portion of which acts as an anchorage for sustaining another portion which extends beyond the supporting pier. A simple cantilever span
286-405: Is to counterbalance each cantilever arm with another cantilever arm projecting the opposite direction, forming a balanced cantilever ; when they attach to a solid foundation, the counterbalancing arms are called anchor arms . Thus, in a bridge built on two foundation piers, there are four cantilever arms: two which span the obstacle, and two anchor arms that extend away from the obstacle. Because of
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#1732798634073312-547: The Niagara Cantilever Bridge by Charles Conrad Schneider (1883) and the Poughkeepsie Bridge by John Francis O'Rourke and Pomeroy P. Dickinson (1889) were all important early uses of the cantilever design. The Kentucky River Bridge spanned a gorge that was 275 feet (84 metres) deep and took full advantage of the fact that falsework, or temporary support, is not needed for the main span of
338-552: The 2012 and 2014 bridge closure periods was provided by Madison, Indiana-based, Madison Milton Ferry LLC, in partnership with Anderson Ferry of Hebron, Kentucky. Passenger ferry service was provided by Madison-based Rockin Thunder Jet Boat Rides LLC during the bridge closure for the final slide. In 15 days over 4000 passengers and 12 dogs were transported in a 6-passenger Jet Boat between Milton Kentucky and Madison Indiana. On March 11, 2014, only four days before
364-410: The girder or truss and meant that longer spans could be built. Several 19th-century engineers patented continuous bridges with hinge points mid-span. The use of a hinge in the multi-span system presented the advantages of a statically determinate system and of a bridge that could handle differential settlement of the foundations. Engineers could more easily calculate the forces and stresses with
390-506: The joints, these bridges will remain standing if the connections between the cantilevers are broken or the suspended span (if any) is removed. Conversely, continuous truss bridges rely on rigid truss connections throughout the structure for stability. Severing a continuous truss mid-span endangers the structure, as exemplified by the collapse of Baltimore's Francis Scott Key Bridge in March 2024. However, continuous truss bridges do not experience
416-411: The need for more strength at the balanced cantilever's supports, the bridge superstructure often takes the form of towers above the foundation piers. The Commodore Barry Bridge is an example of this type of cantilever bridge. Steel truss cantilevers support loads by tension of the upper members and compression of the lower ones. Commonly, the structure distributes the tension via the anchor arms to
442-435: The new bridge began in the fall of 2010, with the old bridge remaining open during work on the piers. Walsh Construction Company planned to close the bridge for only 10 days during construction rather than an anticipated year-long closure. The team used an innovative construction method called "truss sliding" to "slide" the 3,181-foot-long (970 m) truss into place along steel rails and plates. Emergency ferry service during
468-609: The outermost supports, while the compression is carried to the foundations beneath the central towers. Many truss cantilever bridges use pinned joints and are therefore statically determinate with no members carrying mixed loads. Prestressed concrete balanced cantilever bridges are often built using segmental construction . Some steel arch bridges (such as the Navajo Bridge ) are built using pure cantilever spans from each side, with neither falsework below nor temporary supporting towers and cables above. These are then joined with
494-427: The replacement was $ 103.7 million. Continuous truss bridge Although some continuous truss bridges resemble cantilever bridges and may be constructed using cantilever techniques, there are essential differences between the two forms. Cantilever bridges need not connect rigidly mid-span, as the cantilever arms are self-supporting. Although some cantilever bridges appear continuous due to decorative trusswork at
520-470: The shortest distance between Indianapolis, Indiana , and Lexington, Kentucky . The old structure was replaced with a completely new continuous truss which was constructed on temporary piers adjacent to the operational span between 2011 and 2012 and slid into place after demolition of the old span using a construction method called "truss sliding." The new crossing opened to vehicle traffic in April 2014, and
546-482: The tipping forces that a cantilever bridge must resist because the main span of a continuous truss bridge is supported at both ends. It is possible to convert a series of simple truss spans into a continuous truss. For example, the northern approach to the Golden Gate Bridge was initially constructed as a series of five simple truss spans. In 2001, a seismic retrofit project connected the five spans into
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#1732798634073572-461: The truss slide was scheduled to begin, construction workers were installing a mechanism to facilitate the slide when a steel bearing on the southeast corner of the bridge dislodged, causing the bridge to drop by at least 1 foot (30 cm) and injuring one worker. Work was conducted to replace the steel bearing ten days later and the bridge opened to traffic at 7:20 PM on April 17, 2014. The pedestrian path opened on October 30 of that year. The cost of
598-409: Was a major engineering breakthrough when first put into practice, as it can span distances of over 1,500 feet (450 m), and can be more easily constructed at difficult crossings by virtue of using little or no falsework . Engineers in the 19th century understood that a bridge that was continuous across multiple supports would distribute the loads among them. This would result in lower stresses in
624-698: Was begun by the Indiana Department of Transportation and Kentucky Transportation Cabinet on August 26, 2008. The study had to take in account the Madison Historic District , which is a National Historic Landmark , and the National Environmental Policy Act . As of 2009, one of the boons of the new bridge would be to aid a $ 20 million "resort and entertainment center" where a cotton mill once stood. The Indiana Department of Transportation (INDOT), in
650-461: Was started in 1928, and completed in 1929, at the cost of $ 1,365,101.84. It was opened for traffic on December 20, 1929. Originally a toll bridge , on November 1, 1947, at noon the toll was removed. In 1997 the bridge was refurbished. This was after a 1995 study which could not agree on a new bridge location, so $ 10 million was used for the refurbishment. By 2009, as the original bridge was "functionally obsolete" and "structurally deficient." It had
676-916: Was the Boyne Viaduct , built in 1855 in Drogheda , Ireland . The first continuous truss bridge in North America was the Lachine Bridge in Montreal , built in 1888, followed by the Sciotoville Bridge in 1916 and the Bessemer & Lake Erie Railroad Bridge in 1918. Since the development of computer-aided engineering , continuous truss bridges have become more common. Some notable continuous truss bridges, with main span lengths. Most of those listed are in North America; for
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