9416160 Feng The Northridge earthquake of January 17, 1994 caused severe damage to many bridges including the disastrous collapse of seven bridges. Preliminary investigations have shown that some collapses are due to inadequate seat widths at superstructure hinges, although most of them had been retrofitted using cable restrainers. This project investigates the seismic performance of bridges to determine whether energy dissipation systems can be effectively used at bridge hinges and other possible bridge locations for seismic damage reduction. The objectives of this project are to: 1) extensively investigate the performance of cable restrainers at bridge hinge locations during the Northridge earthquake; 2) examine the effectiveness of dampers as hinge restrainers through analysis of bridge response to the ground motion (including the vertical component); 3)examine the effectiveness of dampers installed at bridge abutments and bent caps as restraining devices; and 4) compare different damper devices including viscous, viscoeleastic, friction, and steel yielding dampers and recommend appropriate damper devices and installment configurations suitable for bridge applications. A bridge model of Gavin Canyon Undercrossing which collapsed during the Northridge earthquake will be used for the analysis with the aid of the nonlinear analysis computer code NEABS. Engineers of California Department of Transportation (Caltrans) offered their strong support to ensure the results of this research will be utilized for retrofitting and in the new design of their bridges. Caltrans will provide technical assistance and will make a highway bridge located in seismic-prone San Bernando, California, available for the PI to perform field testing of energy dissipation systems to be recommended as a result of this research. This is a Northridge earthquake project. ***
