The Rocca Roveresca of Senigallia: seismic vulnerability of the de-fensive walls

With the advent of cannons in XV century, many defensive walls underwent retrofitting to improve their capaci-ty to withstand shots of the new powerful weapons. New lines of walls were erected by filling the left space with rubble stone materials. The different strata are characterized by specific behaviours and by well definite dis-continuity surfaces so that the assessment of seismic vulnerability of such kind of defensive walls requires the definition of tailored failure mechanisms. A study on the behavior of the walls of the Rocca Roveresca of Seni-gallia in Italy is presented. A linear finite element model is first developed in order to understand the dynamic behavior of a generic portion of the wall and to detect the probable incipient failure mechanisms. A subsequent static nonlinear analysis is carried out to investigate the formation of the cracking layout and to detect the position of plastic hinges. The last analysis level is carried out by supposing the wall to behave as a set of rigid blocks constituting a kinematic chain subjected to a finite displacement field typical for the collapse situation by introducing the degradation of the behavior of the inner (the less consistent) stratum.