Case Study of Parallel Bridges Affected by Liquefaction and Lateral Spreading

Two parallel adjacent river-crossing bridges performed differently in response to strong shaking (peak ground acceleration ∼0.27  g) and liquefaction-induced lateral spreading during the 2010 M 7.2 El Mayor-Cucapah earthquake. A railroad bridge span collapsed, whereas the adjacent highway bridge survived, with one support pier near the river having modest flexural cracking of cover concrete and a second settling approximately 50 cm. Cone penetration and geophysical test results are presented along with geotechnical and structural conditions evaluated from design documents. This investigation employed an equivalent-static beam-on-nonlinear-Winkler foundation analysis to accurately predict observed responses when liquefaction-compatible inertia demands were represented as spectral displacements that account for resistance from other bridge components. Pier columns for the surviving bridge effectively resisted lateral-spreading demands in part because of restraint provided by the superstructure. Collapse of the surviving bridge was predicted when liquefaction-compatible inertial demands were computed for the individual bent in isolation from other components, and were represented by forces instead of displacements. The poor performance of the settled pier column resulted from bearing-capacity failure in a thin liquefiable layer at the shaft tip.

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  • English

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Filing Info

  • Accession Number: 01595630
  • Record Type: Publication
  • Files: TRIS, ASCE
  • Created Date: Mar 7 2016 3:01PM