Seismic capacity of masonry arches with irregular abutments and arch thickness

•Existing masonry arch bridges need to be assessed in order to know their seismic capacity;•Irregularities in abutment height increase the seismic vulnerability of the arch;•Increasing arch thickness near the impost should have a positive effect;•Limit analysis appears to be reliable for the seismic assessment of masonry arches. The simplest structural analysis for assessing the seismic capacity of a masonry arch is limit analysis. In fact, assuming an equivalent static seismic load, this method can be used to determine the lateral acceleration leading to the collapse mechanism. In this work, applying an analytical procedure, extensive parametric analysis was carried out to describe the seismic capacity of masonry arch structures with irregular geometry. In particular, arches with different abutment heights and discontinuous thicknesses have been examined. The results have been compared against those obtained by finite element analysis and by small scale experimental tests, and a good correlation has been found.