Non-linear finite element analysis and limit analysis comparison of the Caaveiro stone arch bridge

At the present time, there is no accepted procedure to determine the ultimate load that a masonry arch bridge can support. Unlike in the analysis of other structural typologies, it is not common to apply the finite element method to the structural analysis of this construction type. This is because it is rather complicated and expensive to know exactly many of the variables that characterize the structural behaviour of a model, such as material properties, load history, constructive sequence or its own geometric definition. On the other hand, the special configuration of masonry arches, with evident discontinuities in the joints between voussoirs, requires a unique and specific approach to the problem. It is not realistic to consider a totally homogenous structure, as occurs in other typologies and materials. In order to overcome these disadvantages, the purpose of this job is to develop a finite element model, which allows us to know with reasonable reliability, the maximum load that the bridge can support considering all the characteristics of the masonry structures, while keeping the computational cost under acceptable limits. The structure to be modelled is a stone arch bridge located next to the Caaveiro monastery in the northwest of Spain. The finite element model is a two-dimensional plane-stress model considering both geometric, material and contact nonlinearity. The results from this model are compared with those obtained from the limit analysis, considering the hypothesis of the plastic collapse of the structure.