Parametric study of a rapid bridge assessment method using distributed macro-strain influence envelope line

摘要

Dynamic strain-based methods are promising for bridge status assessment; however, the influences of vehicle parameters variations on their capabilities for damage identification are usually indeterminate. In this paper, parametric study for highway bridge rapid assessment method is conducted under moving vehicle loads, which is based on the distributed macro-strain envelope line. First, the relationship between the average bending stiffness and macro-strain history is studied according to the theory of the strain influence line. To determine the influence of different vehicle parameters (velocity, weight and axle numbers) on the method, a 1:10 scale model of a bridge-vehicle system is established for the parametric experimental study. A type of long-gauge Fiber Bragg Grating (FBG) sensor is used in the experiment. The empirical mode decomposition method (EMD) is applied to extract the static macro-strain component, and the maximum values of the static macro-strain histories are accumulated as the long-gauge strain envelope line. The experimental results show that the proposed method not only effectively identifies the location of damage but also damage extent and is not affected by the parameters of the vehicle. This method has engineering significance in bearing capacity evaluation and post-bridge structure reinforcement design. (C) 2018 Published by Elsevier Ltd.