SEISMIC VULNERABILITY ASSESSMENT OF URM WALLS RESTRAINED BY DISSIPATIVE TIES

Dissipative components for steel tie-rods are a new frontier in the field of seismic protection of existing masonry buildings. They can be installed at the extremities of tie-rods for controlling the out-of-plane performance of masonry walls during earthquakes. This paper describes the analytical model of a wall restrained by a dissipative tie consisting of a 2DOF system with viscous-elastic components and boundary conditions also accounting for the sidewalls. Numerical dynamic analyses are performed considering first a reference geometry of a wall restrained by elasto-plastic ties and connected to sidewalls, and secondly a twostorey masonry school built in Italy to show the effectiveness of the device in multiple seismic scenarios. In the second case, the maximum displacement of the restrained wall decreases to about 1/3 of the maximum displacement attained by the unrestrained wall. Moreover, the energy dissipated by the device is 65% of the total seismic input energy.