Numerical Simulation of Base-Isolated Systems Sliding on Concave Surfaces

Base isolation is an acknowledged means to reduce the transmission of earthquakeaccelerations from the ground into the structure. Of particular interest here are systemswhere the bearing slides on a concave surface which produces a self-centering forcerestoring the building to its original position. While the idea behind the technology isstraightforward, the numerical simulation of the structural response is difficult, since thecontact between the bearing and the sliding surface changes continually between stickingand sliding in a nonlinear process. The research presented here aims at developing acomputational model for base-isolated building which would allow the engineer to simulatethe structural response in the time domain in order to find an optimum design of bothbuilding and isolator. It has been shown that a compact 1-DOF system suffices to expressthe general isolated layer response during the excitation. For more general details such asstructural 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.