Detection of debonding in steel-reinforced bridges using wavelet curvature features of laser-measured operating deflection shapes

M S Cao,E Manoach,H Xu,X M Li,W Xu,X Zhu

doi:10.21595/jve.2017.18534

M S Cao, E Manoach + Show 4 more

Open Access

https://doi.org/10.21595/jve.2017.18534

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Abstract

Hidden damage severely threatens the safety of structures due to its invisibility and indistinguishability. Debonding is typical hidden damage in steel-reinforced bridges. Detection of multiple debondings in steel-reinforced bridges poses a challenge for traditional nondestructive methods that require damage location as prior knowledge, but this condition is usually not satisfied for debonding located within the bridge. Differing from existing studies, this study explores a vibrational method of detecting multiple debondings needing no prior knowledge, that uses a scanning laser vibrometer to acquire densely-sampled operating deflection shapes of bridges. The operating deflection shape carries richer information than mode shapes for damage characterization. Nevertheless, densely-sampled deformed quantities are commonly susceptible to noise when used to identify damage. To detect multiple debondings, a new feature is developed, the wavelet-transform curvature operating deflection shape. This feature is used to identify multiple debondings in a steel-reinforced concrete slab dismantled from a bridge, clearly demonstrating the strengths of suppressing noise, intensifying the signatures of debonding, and requiring no prior knowledge of damage location. The proposed method holds promise for detecting multiple hidden damage in various structures besides bridges.

Highlights

Damage can impair the integrity and reduce the performance of a structure, thereby threatening structural safety
As bending stiffness can be reduced in the location of hidden damage such as debonding, the CODS can be employed for hidden damage identification; (ii) a wavelet-transform curvature operating deflection shape (WT-CODS) is derived from the CODS by using the wavelet transform to promote the CODS
This study proposes a new damage feature, WT-CODS, for identification of hidden damage in beam-type structures

Summary

Introduction

Damage can impair the integrity and reduce the performance of a structure, thereby threatening structural safety. The operating deflection shape (ODS) as a generalized mode shape has been increasingly utilized for structural damage detection. DETECTION OF DEBONDING IN STEEL-REINFORCED BRIDGES USING WAVELET CURVATURE FEATURES OF LASER-MEASURED OPERATING DEFLECTION SHAPES. Asnaashari and Sinha [12] utilized a SLV to measure ODSs of a cracked beam excited at a natural frequency, clearly evincing the higher harmonic frequency caused by the crack, respectively. To detect damage while tolerating noise interference, this study aims to develop a sophisticated damage identification method relying on densely-sampled ODSs measured by a SLV. As bending stiffness can be reduced in the location of hidden damage such as debonding, the CODS can be employed for hidden damage identification; (ii) a wavelet-transform curvature operating deflection shape (WT-CODS) is derived from the CODS by using the wavelet transform to promote the CODS. The performance of the WT-CODS is validated in identifying multiple debondings in a steel-reinforced concrete slab dismantled from a bridge model

Formulation of WT-CODS

WT-CODS

Experiment

Multiscale effect of WT-CODS

Conclusions