Abstract
A damage detection method is proposed, which utilizes dynamic displacement of bridge structures under moving vehicle. The problem is first elaborated with closed-form solution of dynamic displacement, which is decomposed into quasi-static component and dynamic component. Dynamic curvature is defined as second derivative of the dynamic displacement for detecting damage location and estimating damage extent. Damage is modeled by local reduction of stiffness in this paper. Numerical study was conducted on a simply supported beam to verify the proposed method. Vehicle model is analyzed with Newmark’s method using Matlab to obtain the contact force acting on the bridge. Beam model is established in commercial finite element software ABAQUS. The effects of road surface roughness and vehicle-bridge interaction are both considered in the analysis. In order to identify damage location and extent, dynamic curvature was calculated with midspan displacement. Parametric study on measurement noise level, damage location, damage extent, and multiple damage cases is performed, and the analysis results show both reliability and efficacy of this method in damage detection of bridge structures. At last, conclusions are drawn for its application to bridges in engineering practice.
Highlights
During the service life of a bridge, factors such as material aging and harsh environmental conditions as well as extreme events such as natural disasters may cause structural damage to varying degrees [1]
W(x) is dynamic displacement instead of static deflection, and Δx is chosen as the length of fundamental natural period. κ(x) is defined as dynamic curvature to distinguish with the curvature calculated with static deflection
Safety of bridges during operation is of much concern for the society, which requires more reliable and efficient damage detection methods
Summary
During the service life of a bridge, factors such as material aging and harsh environmental conditions as well as extreme events such as natural disasters may cause structural damage to varying degrees [1]. There are several difficulties for these frequency domain methods: (1) baseline of previous test data of undamaged structure is needed, which is often unavailable; (2) frequency, as a global modal parameter, is not sensitive to local damage; (3) frequency is often affected by environmental conditions such as temperature or humidity These difficulties have prevented practical use of vibration based methods. A curvature based damage detection method is proposed, which uses dynamic displacement of a bridge subject to loading of a moving vehicle. It does not require baseline of undamaged state of bridge, and both damage location and damage extent can be detected. Conclusions are made for application of this method in engineering practice
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