Research On Arch Bridge Damage Identification Method Based On Wavelet Analysis

Arch bridge has a long history and is one of the earliest widely used bridges inthe world, which has a large span, good durability, beautiful appearance. Due to thereasons of design, construction, improper use, and natural disaster in practicalengineering application, local stiffness degradation, aging, cracks and other damagewould occur in arch bridge. Such damage poses a threat to the safety of bridges andthe life and property of people. Therefore, it is important to obtain the damageinformation of arch bridge timely. In recent years, a time-frequency analysis method-- wavelet analysis method was developed. It is sensitivity to the structural damage,which has a good time-frequency localization characteristics and multi resolutioncapability. Wavelet analysis can decompose the non-stationary and local breakpointsignal in actual structure into different scales of the component, and the waveletcoefficients display the structural damage location directly. Therefore, it hasimportant theory significance and project application value to use this method in archbridge damage identification.This paper used the theory of wavelet analysis and established the damageidentification principle of arch bridge based on wavelet analysis. Through finiteelement analysis for the dynamic characteristics of arch bridge, lanczos method wasused to obtain different modal parameters, chose Haar wavelet as the mother forcontinuous wavelet transform of the damaged arch bridge and got the waveletcoefficient diagram which could identify the damaged location from the signal ofwavelet coefficients. It was established a structure damage identification method ofarch bridge based on wavelet analysis theory.This paper studied a single arch and its arch axis was arc. Solid 3-d element wasused to set up the finite element model. Rotation mode, curvature mode and strainmode was taken to analyze the identification problem of the arch with one andmultiple damaged locations. It established a way to identify the damaged location ofthe arch bridge by the wavelet analysis method based on modal parameters and madecomparison of the identification effects between three modes.This paper studied a two-span deck-type arch bridge and its arch axis was acatenary. Beam element was used to set up the finite element model. Rotation mode,curvature mode and strain mode was taken to analyze the identification problem ofone and multiple damaged locations in the different components (arch ring, bridge deck). And verified the validity of wavelet analysis method for arch bridge damageidentification under different damaged conditions.This paper studied a damaged half-through arch bridge. In order to reflect thedynamic characteristics of arch bridge better, the finite element model used beamelement, pipe element, shell element and bar element. Rotation mode, curvature modeand strain mode was taken to analyze the identification problem of one and multipledamaged locations in different components (arch ring, bridge deck, suspender). Verifythe validity of wavelet analysis method and make comparison of the identificationeffects between three modes. This paper had guiding significance on the damgeidentification of arch bridge.