Seismic Performance of Reinforced Concrete Bridges with Unconventional Configurations

The south connector bridge in the Interstate 5/State Route 14 interchange failed during the 1994 Northridge 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 the study reported in this paper, the nonlinear seismic response history of a bridge model that was based on the new bridge was evaluated relative to that of a conventional bridge. Additional studies were conducted to determine if the conclusions presented in this paper are also valid for skewed bridges. Results showed 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 because it led to large differential displacements at the hinge.