Bridge damage detection by means of displacement based bridge weigh-in-motion

Abstract

In order to develop an efficient and quantitative bridge inspection method using sensors, this study investigates feasibility of bridge damage detection using Bridge Weigh-In-Motion (BWIM) and deflection of the bridge. As deflection influence line changes due to damage in BWIM, a virtual axle is introduced to the vehicle and the process of axle weight identification so that the increase of identified wheel loads due to damage can be distributed to the virtual axle. Bridge damage thus can be detected by examining the wheel load on the virtual axle, which should theoretically be zero if the condition of the bridge has not changed from the reference state. Changes in the wheel load of the virtual axle due to damage in the bridge were observed from a laboratory experiment as well as simulations. The results also indicated that the wheel load of the virtual axle varied depending on the position of the virtual axle and the damage position. Observations demonstrated that the damage identification accuracy by means of the virtual axle can be improved by selecting the appropriate position of the virtual axle.