Experimental and numerical investigations on the effects of radius of curvature and longitudinal slope on the responses of curved bridges subject to seismic pounding

Chiyu Jiao,Junrui Lu,Zhe Sun,Chuang Wang,Peiheng Long

doi:10.1177/00202940211000377

Abstract

Because of the irregular geometries, earthquake-induced adjacent curved bridge pounding may lead to more complex local damage or even collapse. The relevant research is mainly concentrated on the numerical analysis which lack experimental verification and discussion by changing of structural parameters. In this paper, a scaled three-dimensional numerical model of a curved bridge is established based on 3D contact friction theory for investigating the uneven distribution of pounding forces at the expansion joint of the bridge. Shaking table tests were carried out at first on a curved bridge to validate the numerical model. A series of parametric studies were then conducted to examine the impacts of the radius of curvature and longitudinal slope of the superstructure of the curved bridge on its seismic pounding response. The results show that the maximum pounding force first increases and then decreases as the radius of curvature increases, but that it decreases monotonically with the growth of the longitudinal slope. These results suggest that controlling the radius of curvature and the longitudinal slope of the superstructure of the bridge can reduce the localized high stress that is induced by seismic pounding. Also, the unevenly distributed pounding forces can significantly increase the relative radial displacement of the bridge’s deck corners, although the relative tangential displacement may decrease. It is thus necessary to adopt effective anti-pounding measures to prevent the superstructure of the bridge from being unseated.

Highlights

Seismic evaluation of bridge structures are necessary to provide capacity assessments of structures during strong earthquakes
The results showed that the pounding mechanism at the bridge’s expansion joint, including friction pounding with a transverse motion, uneven pounding with a longitudinal motion, and pounding caused by the restraining effect of the limit device, is very complicated
The results show that: [1] the acceleration time history responses of both the bridge deck and pier top obtained from the numerical model were in good agreement with the test results; [2] the peak acceleration of the bridge deck from the numerical analysis was larger than that from the experimental results with errors no exceed 14.9% – this may have been due to different aspects of the tests

Summary

Introduction

Seismic evaluation of bridge structures are necessary to provide capacity assessments of structures during strong earthquakes. Chouw and Hao used the design response spectrum in the Earthquake resistant design codes in Japan and the empirical coherent loss function to simulate the spatial ground motion They studied the influence of the spatial variation of the ground motion and the Soil-Structure Interaction (SSI) effect on the pounding of adjacent bridge structures. Huo and Zhang carried out a three-dimensional numerical analysis of a typical three-span reinforced concrete skew bridge in California, considering the nonlinearity of the pier columns, setting of the expansion joint, and the gap elements at the end of the abutment into account, as well as the pile-soil interaction and the spatial variation of the ground motion.

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Discussion

Conclusions