Effect of radius of curvature on the seismic response of curved bridges

Abstract

Curved bridges have seen widespread application in complex transportation networks, including interchanges and river crossings. If the displacements caused by an earthquake are too large, curved bridges have a greater risk of suffering serious damage due to the rotation of the superstructure. Since curved bridges are more susceptible to damage during earthquakes due to the effect of curvature, this factor also significantly influences the seismic behaviour of curved bridges. The present investigation has ascertained the impact of the radius of curvature on the seismic response of a bridge. The effect of ground motion characteristics and levels of shaking on the performance of bearings has also been studied. It has also been investigated how the bridge responds to seismic activity for both unidirectional and bidirectional effects. To determine the effect of the radius of curvature on the seismic response of the bridges, a non-isolated and isolated curved bridge with high damping rubber bearings has been considered. Bridges with varying radius of curvature (R= ∞, 315m, 157m, and 105m) have been modelled in the finite element-based software SAP 2000, and their response to three different ground motions has been observed. Isolation bearings in a bridge have been found to be more effective against seismic loads. The performance of an isolated bridge is superior to that of a non-isolated bridge when isolation bearings are installed in all of the piers and abutments. It is observed that a lower radius of curvature increases the deck displacement. It is also observed that bidirectional loading increases the seismic response of the curved bridge significantly relative to unidirectional loading.