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Bridge Bent System for Seismic Regions
Highways for LIFE Technology Partnerships 2009 Award $400,397
PDF Version (3.4 mb)
Need for Innovation
Prefabricated bridge bents, also known as piers, have not been used in seismic regions because accepted methods of making connections that are both structurally robust and quick to assemble were not known and were not addressed in design specifications. This new technology allows the main elements of bridge bents to be prefabricated off site. Then the segments are moved into place and assembled to form the bents, greatly reducing construction time and traffic delays.
The BergerABAM project team has demonstrated, on a bridge in Washington State, a totally precast concrete bridge bent system, including precast columns and beams, that can be used in seismic regions. To construct precast elements in high seismic zones requires ductile detailing, which permits the structure to deform rather than to experience sudden unexpected brittle failure. The connections are made with a small number of large-diameter reinforcing bars that are grouted into larger-diameter ducts. This is the first project in the U.S. to use such precast, segmental construction for bridge bents in high seismic regions.
Laboratory testing of both column-to-spread footing connections and column-to-drilled shaft connections have been completed. The demonstration project, a new bridge over Interstate 5 in Washington state is now complete and open to traffic. The final reports, draft design specifications and design examples are currently being completed.
Completed HFL Precast Bent
Precast Bent Exploded View
Critical Components of System: Two Connections
Previous Test Results
Beam-Column Connection Tests
Socket Footing Testing
Both spread footing and drilled shaft connections have validated by testing in the laboratory. Both types were able to restrict seismic damage to the column.
Highways for Life
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