Lateral Impact Resilient double concave Friction Pendulum (LIR-DCFP) bearing: Formulation, parametric study of the slider and three-dimensional numerical example

Seismic isolation has been one of the best alternatives in protecting structures, being frictional isolators one of the most used devices in constructing isolation systems. Under extreme seismic inputs, the impact between the inner slider and the restraining rims of the plates could occur. This internal impact has been indicated as one of the main contributors to the failure of frictional pendulum bearings. This paper presents a new type of frictional device, the Lateral Impact Resilient double concave Friction Pendulum (LIR-DCFP) bearing. This device has an improved inner slider that enhances the dynamic behavior if the lateral capacity of the isolator is overcome. The three-dimensional formulation of the LIR-DCFP bearing is presented and proposed to perform dynamics analyzes. A parametric analysis was performed to evaluate the influence of the geometry of the inner slider. Finally, a comparative three-dimensional analysis between the dynamic response of a structure isolated using LIR-DCFP bearings and double concave Friction Pendulum (DCFP) bearings is presented. Important reductions in the base shear, inter-story drifts, and absolute accelerations are achieved using LIR-DCFP bearings.