Seismic analysis and assessment of a skew highway bridge

摘要

The seismic response of a skew reinfored concrete box girder bridge-the Foothill Boulevard Undercrossing--is analyzed and studied using finite element models. The effects of superstructure flexibility, substructure boundary conditions, structural skewness and stiffness eccentricity are assessed using spectral analyses. The results shw that show that the internal forces and displacements of the supporting columns as well as the displcement of the deck will be underestimated if one neglects the flexibility of the the bridge deck. The study also deomonstrates that the seismic response of the brideg is affectd quite noticeably by the boundary conditions of the bridge columns and the overall skewness of the bridge. Based on this study, a theory to explain the failure of this bridge is presented.