Seismic Vulnerability Analysis of Concrete-Filled Steel Tube Tied Arch Bridges Using Symmetrically Arranged High-Damping Rubber Bearings

Abstract

High-damping rubber bearings play an essential role in isolated bridges. They can prolong the natural vibration period of a bridge and reduce its seismic response. In order to quantitatively study the isolation performance of high-damping rubber bearings, this paper investigates a concrete-filled steel tube-tied arch bridge as the research object and uses symmetrically arranged high-damping rubber bearings for isolation reconstruction. Nonlinear finite element analysis models for isolated and non-isolated bridges are built based on the structural properties of the actual bridge. Based on the structural deformation failure criterion, a bridge damage evaluation index system is established, the damage index of each component is defined, and a quantitative analysis of different damage states is carried out. Based on the incremental dynamic analysis method, the seismic vulnerability curves of bridge components and systems are established. By comparing the seismic vulnerability curves of the bridge before and after isolation, the isolation effect of the high-damping rubber bearings is quantitatively evaluated. The results of the analysis show that the high-damping rubber bearings have a significant isolation effect on the bridge structure and the effect is symmetrically distributed along the longitudinal symmetry plane of the bridge. After adopting the isolation measures, the exceedance probability of damage of each component of the bridge is reduced to varying degrees. Among them, the isolation effect on piers and arch ribs is the most significant, up to more than 90%. At the same time, the exceedance probability of damage of the bearing itself is less reduced. This result is also consistent with the original intention of the design of the isolation bearing; that is, through the energy dissipation of the isolation bearing, the seismic response of other components of the bridge is reduced.