Damage Detection of a Continuous Bridge from Response of a Moving Vehicle

Z H Li,F T K Au

doi:10.1155/2014/146802

Abstract

This paper presents a multistage multipass method to identify the damage location of a continuous bridge from the response of a vehicle moving on the rough road surface of the bridge. The vehicle runs over the bridge several times at different velocities and the corresponding responses of the vehicle can be obtained. The vertical accelerations of the vehicle running on the intact and damaged bridges are used for identification. The multistage damage detection method is implemented by the modal strain energy based method and genetic algorithm. The modal strain energy based method estimates the damage location by calculating a damage indicator from the frequencies extracted from the vehicle responses of both the intact and damaged states of the bridge. At the second stage, the identification problem is transformed into a global optimization problem and is solved by genetic algorithm techniques. For each pass of the vehicle, the method can identify the location of the damage until it is determined with acceptable accuracy. A two-span continuous bridge is used to verify the method. The numerical results show that this method can identify the location of damage reasonably well.

Highlights

The safety of bridge structures is very important to economic development of all countries, so it is very important to make sure that the bridges are in good condition
In the short-time Fourier transform method, the total time interval is divided into shorter time intervals for the fast Fourier transform to be applied to each interval
A multistage multipass strategy is proposed to identify the location of damage from the response of a vehicle moving over a bridge considering the road surface roughness

Summary

Introduction

The safety of bridge structures is very important to economic development of all countries, so it is very important to make sure that the bridges are in good condition. Wavelet transform allows variable-size windows and this is why it is called a mathematical microscope This property makes it a suitable method for detection of damage from a response [8]. The authors previously applied a modal strain energy based damaged detection method to analyze the response of the vehicle [16] and came up with two possible locations of the damage. This is due to the limitation of the frequency-based damage detection methods [17]. Modal strain energy based method can narrow down the search space for GA algorithms to save computational time and improve the chance of getting the correct solution

Vehicle-Bridge Interaction System

Multistage Multipass Damage Detection Method

Numerical Study

Findings

Conclusions