Seismic collapse analysis of stone arch bridges

The present paper deals with the collapse behavior of an historical stone arch bridge. Ancient stone or masonry arch bridges are still a useful and a not rare engineering road in Italy, as well as in other parts of Europe. Some of the most ancient arch bridges are concentrated in Italy and constitute an integral part of the Italian transportation system. They also represent a valuable engineering achievement of the people that have lived in Italy for centuries and a cultural heritage of the world. A finite element modal analysis and seismic load evaluation has been performed building a suitable program code. The assessment of the collapse and shakedown states, related to a nonlinear constrained optimization problems, has been analyzed using lower bound and Bleich-Melan theorems of limit analysis. Whereas the retrofitting of this stone structure cannot be executed in the intrados surface of the stone vault, so that an application of CFRP strips on the arch extrados is a more useful constructive technique, especially if a significant increase of the limit and shakedown load multipliers occurs