Comparative response assessment of base-isolated braced-frame buildings considering effects of ductility design

Abstract

This paper evaluates seismic responses of steel concentrically bracing frames isolated by double friction pendulum bearings with two levels of ductility. The seismic responses of base-isolated buildings are compared to their comparable fixed-base buildings. For this purpose, two isolated and two conventional concentrically braced-frame low-rise buildings are seismically designed, and their three-dimensional finite element models are developed in OpenSees. To investigate the impact of ductility, seismic responses of both ordinary and special levels of ductility are computed and analyzed. The results indicate that the ductility levels significantly affect seismic responses of base-isolated buildings. The superstructure with special level of ductility decreases the peak floor acceleration compared to the ordinary ones. The maximum reduction is calculated by about 20%. Moreover, special ductility level increases peak drift demand compared to the ordinary ones up to 75% in base-isolated buildings. Furthermore, the results show that the ordinary superstructure reduces the maximum and residual displacement of double friction pendulum bearings compared to the special ones. • Effects of level of ductility on seismic responses of isolated concentrically braced-frame buildings. • Seismic assessment of buildings with double friction pendulum bearings. • Comparative response evaluation of base-isolated and conventional steel frames. • Considering different hazard levels in assessment of base-isolated buildings.