Analytical Study of Triple Friction Pendulum Under a Different Hazard Level of Earthquakes

The triple friction pendulum (TFP) system is a new generation sliding isolation having four spherical sliding surfaces with three effective pendula. Due to multiple sliding surfaces, TFP system shows highly adaptive behaviour under different hazard level of earthquakes, despite being a passive system. In this research work, a mathematical model and seismic response pertaining to TFP system under maximum considered earthquakes have been described. Series model composed of existing nonlinear element is described along with its hysteretic force–displacement behaviour. Effective period and effective damping in combination with desirable displacement capacity of TFP bearing designs are considered. Due to the presence of multiple sliding surfaces, sliding displacement is distributed over the multiple surfaces and seismic energy is dissipated. It is also found that, at low input, TFP bearing stiffens. It gets soften with the increase in input. And, it gets stiffen against higher levels of input. Thus, it shows highly adaptive behaviour under different hazard levels of earthquake.