Theoretical study of moving force identification on continuous bridges

A method to identify moving forces on a continuous bridge has been developed in this paper. The bridge is modelled as a Bernoulli–Euler beam and the boundary value problem of the beam is solved to get the exact mode shape functions of the vibrating beam with intermediate supports. As the number of spans of the bridge increases, the identification accuracy decreases and at the same time more execution time is needed to finish one case study. To minimize this problem, a method has been developed to identify moving forces on a selected span of interest from the continuous bridge. The Singular Value Decomposition (SVD) of the coefficient matrix of the overdetermined equation is used in the solution. To evaluate the method, simulations of two moving forces on a continuous bridge and on one selected span from the continuous bridge are studied. White noise is added to the simulated bending moment and acceleration responses to study the effect of noise in moving forces identification problem for different numbers and arrangements of sensors. The results obtained from the simulation study show that the method is effective in identifying moving forces and acceptable results can be obtained.