Vehicle-bridge coupling dynamic response of a box bridge after reinforcement with prestressed CFRP

Bo Liu,Wenting Zhang,Xuansheng Cheng,Xiangdong Cai

doi:10.21595/jve.2020.21274

Abstract

The dynamic response of vehicle bridge coupling before and after strengthening with post-tensioned carbon fiber reinforced polymer (CFRP) is analyzed. To obtain a better dynamic response of vehicle bridge coupling, the theory of vehicle moving load is deduced and transformed. To obtain the dynamic response of the vehicle bridge coupling before and after the post-tensioned CFRP reinforcement, a numerical model of the vehicle bridge coupling before and after the post-tensioned CFRP reinforcement is established, and the vertical acceleration time history curve and vertical displacement time history curve of the 1/4, 1/2, and 3/4 sections of the side span and the middle span of the bridge before and after post-tensioned CFRP reinforcement are obtained under different speeds of heavy vehicles. The results show that with the increase in vehicle speed, the vertical displacement of the bridge has almost no change, but the increase in the vertical acceleration peak value is obvious, which results in a faster arrival of the vertical displacement and the vertical acceleration peak value and also causes the amplitude of the vertical acceleration of the bridge to increase greatly, and the vertical acceleration increase in the side span is significantly larger than that in the middle span. Post-tensioned CFRP can effectively reduce the vertical displacement and acceleration of the bridge, but there are some deficiencies in reducing the vertical displacement of the bridge. With the increase in speed, the effect of the post-tensioned method is better.

Highlights

Because of the complex environment of the current transportation industry, the overloading of large trucks has become a common phenomenon
Omar [2] studied the shear fatigue behavior of reinforced concrete (RC) T-beams strengthened with carbon fiber reinforced polymer (CFRP) composite materials and obtained the effectiveness of a CFRP strengthening system for prolonging the fatigue life of structures via experiments
Assuming two cars move at a certain speed relative to one another at the same time through the bridge, in the process of choosing which side of the lane uses FEM to analyze the dynamic response of the bridge, the mobile vehicle is simplified by a constant force moving at a constant speed

Summary

Introduction

Because of the complex environment of the current transportation industry, the overloading of large trucks has become a common phenomenon. It is necessary to analyze the vehicle-bridge coupled dynamic response before and after reinforcement with prestressed CFRP, and much progress has been achieved in the study of bridge reinforcement. Scholars, such as Ai et al [1], have derived the quantitative relationship between the natural frequencies of pretension and the damage of RC beams theoretically. By using finite element software in combination with the data of an actual bridge, a numerical vehicle-bridge coupled model before and after reinforcement with CFRP is established, and the influence of different speeds of heavy vehicles on the dynamic response of vehicle-bridge vibration coupling before and after reinforcement with post-tensioned prestressed CFRP is studied

Theory of moving constant force

Transformation of vehicle moving load

Pre-reinforcement model

Post-tensioned reinforcement model

Design

Dynamic response of the vehicle-bridge coupling system

Findings

Conclusions