Investigations of the effects of a passive bumper on the seismic response of base-isolated buildings: Experimental study and parameter optimization

The horizontal displacement values experienced by the isolation layer of base-isolated buildings can exceed the allowable range and cause failures during the rare or very-rare earthquakes. Excessive horizontal displacements of the isolation layer may cause collisions between the building and retaining walls of the isolation ditch and even cause the collapse of the isolated building. This paper proposes a cost-effective, easy-to-build, passive bumper device, called Flexible Limit Protective Device (FLPD) in order to act as shock-absorbers. Through numerical simulations and experiments, the nonlinear behavior of the FLPD is investigated. Subsequently, through structural simulations, the effectiveness of using FLPDs is studied. The elitist non-dominated sorting genetic algorithm (NSGA-II) is used to optimize the design of FLPDs, and the response of structures equipped with optimized FLPDs are simulated numerically. The results indicate that proposed optimized FLPDs can effectively work as shock-absorbers for base-isolated structures. This paper can provide a guideline for the design of shock-absorbers.