Seismic Design and Performance Evaluation of Controlled Rocking Masonry Shear Walls without Posttensioning

AbstractUnbonded posttensioned controlled rocking masonry walls (PT-CRMWs) have been increasingly studied in the last decades due to their promising results regarding seismic resilience. However, implementing posttensioning (PT) has still some drawbacks, such as construction challenges, PT losses, and yielding during a seismic event. In response, this study investigates a newly proposed energy dissipation-controlled rocking masonry wall (ED-CRMW), which eliminates the use of unbonded posttensioned bars and relies instead on gravity loads to self-center the wall to its vertical plumb while incorporating an energy dissipation (ED) device to limit seismic displacements. The study presents a design approach for the proposed system, including the influence of higher mode effects. In this respect, a multispring macro model is developed using OpenSees and validated against recent experimental results by the authors. Next, as no distinct values are yet provided in ASCE 7, the seismic response modification factor is investigated using collapse risk analysis. Specifically, using the validated model, nonlinear static and dynamic analyses are performed to 20 ED-CRMW archetypes with different design configurations. The results demonstrate that the design objectives were achieved and that a seismic response modification factor of 7 assigned to the selected design configurations meets the FEMA P695 acceptance criteria for seismic collapse risk under the maximum considered earthquake (MCE).