Mitigation of Vertical and Horizontal Seismic Excitations on Bridges Utilizing Shape Memory Alloy System

Abstract

Vertical seismic excitation has a tremendous effect on bridges and many researchers have pointed out bridges damages occurred during the past significant earthquakes which were direct results of ignoring vertical acceleration of ground motions. Many studies have emphasized the importance of extending practical methods to reduce effects of vertical acceleration of earthquakes besides effects of horizontal accelerations; but no practical method has proposed up to now. In this article, an innovative shape memory alloy system is proposed for bridges that can simultaneously controls effects of vertical and horizontal seismic excitations on bridge and reduce them. To evaluate the effectiveness of the shape memory alloy system, a nonlinear time history analysis is conducted on a detailed three-dimensional model of a multi-span simply supported bridge using a representative ground motion. The results show that the proposed new system is very effective for reducing effects of vertical and horizontal seismic excitations on bridges.