Numerical Simulation of Base-Isolated Systems Sliding on Concave Surfaces

Base isolation is an acknowledged means to reduce the transmission of earthquake accelerations from the ground into the structure. Of particular interest here are systems where the bearing slides on a concave surface which produces a self-centering force restoring the building to its original position. While the idea behind the technology is straightforward, the numerical simulation of the structural response is difficult, since the contact between the bearing and the sliding surface changes continually between sticking and sliding in a nonlinear process. The research presented here aims at developing a computational model for base-isolated building which would allow the engineer to simulate the structural response in the time domain in order to find an optimum design of both building and isolator. It has been shown that a compact I-DOF system suffices to express the general isolated layer response during the excitation. For more general details such as structural accelerations and drift a set of coupled differential equations must be solved. Finally, through comparison of the behavior of an isolated structure with a fixed-base one, the efficiency of sliding isolation is demonstrated.