Seismic Performance of Reinforced Concrete Bridges with Unconventional Configurations

TLDR: The south connector bridge in the I-5/State Route 14 interchange failed during the 1994 Northridge (California) earthquake because of concentration of shear forces in the short columns near the abutments as discussed by the authors.

Abstract: The south connector bridge in the I-5/State Route 14 interchange failed during the 1994 Northridge (California) earthquake because of concentration of shear forces in the short columns near the abutments. In the replacement bridge, the column heights were made uniform and other changes were made with respect to supports near the expansion hinges and hinge connectivity. In this study, the nonlinear seismic response history of a bridge model based on the new bridge was evaluated relative to that of a conventional bridge. Additional studies were conducted to determine if the conclusions presented here are also valid for skewed bridges. Results show that the new design is successful in accomplishing a uniform shear distribution in columns only if abutment shear keys are designed to fail under moderate amplitude ground motions. The lack of continuity in the hinge is a drawback of the new design as it led to large differential displacements at the hinge.