ABSTRACT
The moving load identification techniques described in previous chapters have good accuracy for identification but they demand extensive computation with a vehicle crossing a multi-span bridge structure. The finite element approach is flexible when dealing with vehicle axle-loads moving on top of a bridge structure with complex boundary conditions. The method has efficient computational performance and good identification accuracy, especially with the orthogonal function smoothing technique to obtain the velocities and accelerations from the measured strains. This chapter introduces the finite element model approach. The Interpretive
Method I is discussed in Section 9.2.1, in which the bridge is modeled as an assembly of lumped masses interconnected by massless elastic beam elements. The Euler-Bernoulli beam model is used in the Interpretive Method II described in Section 9.2.2. The use of structural condensation technique to reduce the DOFs of the structure to have a determined set of identification equation is revisited in Section 9.2.3. Numerical simulation and experimental results in Sections 9.3 and 9.4 demonstrate the efficiency and accuracy of the method to identify the moving loads. A comparative study with the Exact Solution Technique Method is also presented in Section 9.5.
