A Simplified Model for Investigation on the Effects of Seismic Actions on Masonry Arch Bridges

摘要

Masonry bridges are vulnerable structural systems to the ground motion excitation and their survival in case of such incidents has to be studied in detail. In this work, a simplified model for dynamic analysis of masonry bridges based on rocking motion of rigid blocks is proposed. Using this model, nonlinear time integration analysis on these bridges can be done with ease and in a short time. The proposed model was used in evaluation of seismic performances of a monumental masonry bridge subjected to both horizontal and vertical seismic actions. The study shows the importance of vertical component of ground motion in determination of internal forces and shear sliding deformation at bottom of the bridge's pier. The proposed model has also shown its ability in defining the effectiveness of a seismic retrofit approach for the same bridge system in a comparative study. According to this investigation, seismic performances of the bridge can be significantly improved in case of adding ductility to its deck assembly.