IDENTIFICATION AND PARAMETRIC ANALYSIS OF MOVING LOADS ON SIMPLY SUPPORTED AND MULTI-SPAN CONTINUOUS BRIDGES

Moving loads identification is one of the important measures for health monitoring of bridge because the cyclic action of moving loads may lead to fatigue damage or even failure of the bridge. The identification and parametric analysis of moving loads on simply supported and multi-span continuous girder bridges are performed using the spline approximation method. Based on the modal superposition method and the exact solution of beam nature vibration, the motion equations of the simply supported and continuous girders subjected to a set of moving loads are established. Bridge strain responses are approached through spline least-squares method, and their derivatives are obtained by means of spline numerical differentiation. Then the regularized solution is obtained using Tikhonov regularization and singular values decomposition. The simulation analysis is carried out for a simply supported and a 3-span continuous girders, and the parametric analysis for some influence factors are completed. Some former experimental data are also used to verify the reliability of this method. The results show moving loads on both simply supported and multi-span continuous girder bridges may be identified effectively using the spline approximation method, in which more powerful practicability and noise-proof performance arepresented. The identification accuracy and the noise-proof performance of moving loads on simply supported girder bridge is higher than those on continuous girder. Stable solutions of moving loads may be obtained through Tikhonov regularization, which may increase the identification accuracy and reduce the sensitivity on measuring noise.