Near-Fault Seismic Response Analysis of Bridges Considering Girder Impact and Pier Size

Wenjun An,Guquan Song,Shutong Chen

doi:10.3390/math9070704

Abstract

Given the influence of near-fault vertical seismic action, we established a girder-spring-damping-rod model of a double-span continuous girder bridge and used the transient wave function expansion method and indirect modal function method to calculate the seismic response of the bridge. We deduced the theoretical solution for the vertical and longitudinal contact force and displacement response of the bridge structure under the action of the near-fault vertical seismic excitation, and we analyzed the influence of the vertical separation of the bridge on the bending failure of the pier. Our results show that under the action of a near-fault vertical earthquake, pier-girder separation will significantly alter the bridge’s longitudinal displacement response, and that neglecting this separation may lead to the underestimation of the pier’s bending damage. Calculations of the bending moment at the bottom of the pier under different pier heights and cross-sectional diameters showed that the separation of the pier and the girder increases the bending moment at the pier’s base. Therefore, the reasonable design of the pier size and tensile support bearing in near-fault areas may help to reduce longitudinal damage to bridges.

Highlights

Damage to bridges resulting from earthquakes only affects the traffic, and affects rescue operations after the disaster
It is difficult to repair bridges damaged by an earthquake, which seriously affects the early recovery of transportation [1,2]
Vertical seismic action changes the axial force of the pier, and the increased axial force may cause the pier to be damaged under compression [8,9,10,11]

Summary

Introduction

Damage to bridges resulting from earthquakes only affects the traffic, and affects rescue operations after the disaster. Vertical seismic action changes the axial force of the pier, and the increased axial force may cause the pier to be damaged under compression [8,9,10,11]. A number of experiments have been conducted to examine the possible bending and shear damage caused by the axial force on the pier, and it has been proposed that under the action of a vertical earthquake, the fluctuation of the axial force will have an impact on the shear performance of the pier [12,13,14,15]. When the axial force of the bridge pier decreases or tensile stress occurs, it will reduce the horizontal shear resistance of the concrete, causing the shear strength of the pier to diminish. The vertical seismic action will increase the mid-span bending moment and cause structural damage [12,16]

Objectives

Results

Conclusion