Non-linear seismic analysis of base-isolated RC frame structures

In this paper, seismic analysis of plane RC frame structures with High Damping Rubber Bearings (HDRBs) base-isolation systems is performed in the non linear range. For RC members, a modified version of hysteretic Park model is used. For HDRB isolators, a new hysteretic model is presented, which is able to accurately predict the mechanical response in the large strain range. The dynamic equilibrium equations are solved making use, at each time step, of a block iterative Newton-Raphson scheme: the frame is divided into superelements (beams and columns) with master nodes at the extremities and internal local nodes for the computation of relations between end moments and relative rotations at superelement extremities. The effectiveness of HDRB base-isolation systems to reduce inelastic deformations in the RC superstructures is investigated through some numerical examples.