Modeling of Masonry Bridges in Presence of Damage: The Case Study of San Marcello Pistoiese Bridge

Safeguard of the heritage of masonry infrastructural constructions is a relevant concern nowadays. The historical-monumental value of a large part of these artifacts, combined with their current functional reuse in the transport net-works, make them interesting case studies. These structures are generally afflicted by structural weaknesses that make them vulnerable under dynamic actions, strongly present in the Italian peninsula, due to its widespread and high seismicity. In this framework, Finite Element analysis turns out to be a useful tool to better understand the structural behavior of masonry artifacts. In this paper, the seismic assessment of a masonry arch bridge, located in Italy, is proposed by means of a 3D FE modeling. The masonry material is described through the adoption of a constitutive law with damage, capable of capturing the degrading behavior of masonry under cyclic actions, characterized by a strain softening response. The phenomenological law is characterized by the presence of a scalar damage vari-able, describing the material degradation evolving during the analysis. After the investigation of modal shapes of the bridge, the horizontal capacity curve was estimated through a pushover analysis, and finally the structure was subjected to a set of natural accelerograms. The health state of the case study was consequently defined by means of damage indexes, and the most critical areas of the bridge were highlighted through the study of the damage patterns.