Keywords: Uplift-restraint isolation systems. Seismic isolation. Friction pendulum isolator. XY-FP isolator. Behavior. Experimental tests. Steel-frame models. Uplift prevention. Displacement. Energy dissipation. Stiffness. Bearings. Integration. 3D-BASIS-ME. Analytical studies.
Abstract: This report describes the development of a novel uplift-prevention Friction Pendulum isolator called the XY-FP. It presents the principles of operation and mathematical model of the XP-FP isolator, describes its mechanical behavior through testing of a single isolator, and demonstrates its effectiveness through testing of a quarter-scale steel-frame model structure. The computer program 3D-BASIS-ME was modified to include an element representative of the mechanical behavior of the new XY-FP isolator, and the validity and accuracy of analytical methods to predict its behavior is assessed. The study shows that the XY-FP isolator provides effective uplift prevention regardless of the state of displacement in the bearing, allows for decoupling of the bi-directional horizontal motion along two orthogonal directions, and has the capability to provide distinct stiffness and energy dissipation along the principal directions of the bearing. In addition, by encompassing much less structural material, the isolator offers a lighter and more economical alternative to the standard Friction Pendulum bearing. Moreover, it provides an architecturally flexible solution in terms of integration into a structural system when space considerations are important.