Effect of the arc-surfaced dampers on the collapse probability induced by pulse-like earthquakes

Abstract

Since the friction dampers possess constant friction forces, they cannot play a significant role in mitigating the strong earthquakes' demands. The application of the variable-force friction dampers is one way of circumventing this problem. In this paper, the design parameters of a specific force-variable friction damper namely Arc-Surfaced Friction Dampers (ASFD) have been investigated and their effect on the efficiency of their performance has been assessed. To this end, a 4-story structure designed according to Iranian Building Code Standard-2800 equipped with an ordinary frictional damper (LSB) and an ASFD has been excited by an ensemble of near- and far-field ground motions. To determine the optimal ASFD parameters, which in here reflected as the initial sliding force and the radius of curvature of the ASFD, the response of the structure due to 44 FEMA-p695 ground motions scaled to the elastic design spectra corresponding to 10% of exceedance in 50 years are estimated. The nonlinear dynamic analysis has provided a basis to define the optimal parameters concerning the life-safety and collapse-prevention performance. The results showed that implementing the ASFD as a control device has significantly reduced the median spectral acceleration corresponding to the onset of collapse compared to the uncontrolled structures.