Experimental and analytical studies of structures seismically isolated with an uplift-restraining friction pendulum system

Abstract

SUMMARYThis paper presents ÿndings from a comprehensive analytical and experimental study on the upliftrestraining XY-FP sliding isolation system. To investigate the e ectiveness of the XY-FP isolator and provide a rational basis for evaluating the e cacy of the developed mathematical model, an extensive experimental program was conducted on the earthquake simulator at the University at Bu alo. The experimental program involved a slender, ÿve-storey, scale-model frame seismically isolated with four XY-FP isolators subjected to simulations of historical horizontal and vertical ground motions. The experimental response demonstrates the validity of the concept and provides evidence for the e ectiveness of the XY-FP isolator in preventing uplift. A comprehensive analytical model capable of emulating the mechanical behaviour of the XY-FP isolator is developed and implemented in program 3D-BASIS-ME. The newly enhanced program is used to predict the dynamic response of the seismically-isolated model structure. Comparison of analytical predictions with experimental results attests to the e cacy of the analytical model for simulating the response of the XY-FP isolator. With its appealing conceptual simplicity and its proven e ectiveness, the new uplift-restraining isolator has the potential to facilitate the application of seismic isolation even under the most extreme of conditions, including but not limited to near-fault strong ground motions and uplift-prone structural systems.

A Review of Seismic Isolation for Buildings: Historical Development and Research Needs

“…The use of pre-stressing tendons was evaluated by Kasalanati and Constantinou [84]. Another solution is the tension capable XY-FP bearing mentioned earlier [50,51] that has been implemented in several applications. An alternative practical solution is to pair elastomeric bearings with tension capable cross-linear bearings [85].…”

“…In certain situations uplift in the bearings could occur, e.g., bearings on the perimeter of slender structures or those located under braced frames. For these situations resistance to uplift is considered desirable and a tension-capable sliding bearing, based on the principles of the single FP bearing, was developed [50,51]. The tension-capable device, referred to as the "XY-FP" isolator, consists of two orthogonal concave sliding rails connected through a sliding device that couples the rails in the vertical direction, allowing for the development of tensile forces in the bearing.…”

Uplift-restraining Friction Pendulum seismic isolation system

“…Thus, the side contact surface of the lower beam is acted upon a normal force of magnitude |F 2 |, which results in increasing the friction force on the lower beam, should motion along axis 1 occur. Analogous considerations can be made for the e ect of lateral force F 1 on F f2 as dictated by Equation (9).…”

A State-of-the-Art Review of Seismic Isolation Technology in Bridge Engineering

“…Structures with large height-width ratio, bridges with large distance between the superstructure barycenter and bearing may result in a tensile behavior of the isolation bearing. Thus the anti-uplift FPS has been developed in recent years (Rossis and Constantinou, 2005). Then, some scholars improved the existing FPS and proposed the variable curvature friction pendulum isolation system (Tsai et al, 2006), the double concave friction pendulum isolation system (Malekzadeh and Taghikhany, 2010;Deng et al, 2010) and the triple curvature friction pendulum isolation system.…”