Limit analysis of a single span masonry bridge with unilateral frictional contact interfaces

In this paper is studied the ultimate failure (limit) load of stone arch bridges. The proposed model is based on finite element analysis with interfaces, simulating potential cracks, which allow for unilateral contact with friction. Opening or sliding of some interface indicates crack initiation. The ultimate load has been calculated by using a path-following (load incrementation) technique. Lack of a solution at a certain level of loading indicates onset of failure. For the validation of the proposed method, which is based on the contact model, the ultimate failure load is recalculated by using a modern implementation of the classical collapse mechanism method based on linear programming. Finally, the beneficial effect of the fill on the limit load of a real bridge is estimated and compared with experimental results.