Structural capacity of masonry arch bridges to horizontal loads

This work deals with the seismic vulnerability evaluation of existing masonry arch bridges. A parametric study has been carried out to determinate how the capacity curve of the arch changes with its geometric configuration, in the hypothesis of infinitely rigid abutments. The capacity curve is obtained by means of a limit analysis approach. The study is aimed to identify on one hand the horizontal load multiplier that activates the kinematic mechanism, on the other hand the collapse displacement. The numerical results of the structural capacity so found have been compared with the results available in literature. In parallel, the structural capacity of arch bridges with span up to 1.5m has been evaluated. In this case, also the abutments participate to the kinematic mechanism. After identifying the most probable collapse mechanism, a parametric study has been carried out to evidence the influence of passive earth pressure on the capacity curve trend.