Damage identification of bridge structure based on frequency domain decomposition and strain mode

Jiaquan Wu,Kun Ma,Fei Ye,Hongyan Li

doi:10.21595/jve.2019.20154

Abstract

Because it is difficult to determine the degree and location of damage to bridge structures under environmental excitation, a new method combining frequency domain decomposition and strain mode identification for bridge structure damage assessment is proposed and the related identification principle is derived. General variations in the strain mode parameters of different reinforced concrete beam damage states are accordingly studied under ambient excitation. The results show that the proposed strain mode identification method based on frequency domain decomposition has good anti-noise performance and can identify the strain mode parameters of a structure relying solely on the strain response information of the structure, even under strong background noise. The mutation of the strain mode was effectively used to determine the damage condition of reinforced concrete beams, and the adaptability, feasibility, and reliability of the proposed method for modal parameter and damage identification of reinforced concrete beams under environmental excitation were verified.

Highlights

Reinforced concrete beams constitute one of the primary structural forms of highway bridges, regardless of bridge size
The frequency domain decomposition (FDD) method and strain mode were combined to provide a method for the identification of damage to a reinforced concrete beam bridge structure under environmental excitation
The theoretical derivation of the frequency domain decomposition method (FDD) method indicates that it is suitable for the modal identification of strain vibration signals

Summary

Introduction

Reinforced concrete beams constitute one of the primary structural forms of highway bridges, regardless of bridge size. The FDD method has been widely studied in the identification of structural modal parameters [17,18,19,20] This type of research primarily uses acceleration sensors to collect the structural vibration response information and obtain the displacement mode. This study combines the FDD method with the strain mode, which is sensitive to the damage of the structure, to identify simulated damage to precast reinforced concrete beams under environmental excitation. The modal frequency and damping are identified by the logarithmic attenuation method It can be seen from the above theoretical derivation that the strain mode identification method based on FDD contains similar expressions to the traditional FDD method, and can be used for structure modal parameter identification. After identifying the strain mode parameters of the tested structure and comparing them with those calculated for an intact structure, the damage state and damage degree of the structure can be determined according to the change in the structural strain mode parameters

Experiments

Damage identification

Findings

Conclusions