Evaluación de la influencia de la intensidad del registro sísmico en el comportamiento de estructuras flexibles aisladas de la base.

Abstract

The objective of the present work is to investigate the efficiency of base seismic isolation as a function of building flexibility and seismic recording intensity. Ten structural models of discretized masses ranging from 3 to 39 degrees of freedom were developed. Linear elastic behavior was considered in all degrees of freedom. In addition, a base isolation system was considered by adding one degree of freedom to the embedded systems. The degree of freedom of the isolation system considers a nonlinear behavior based on the criteria defined in Aroca (2021). The systems were subjected to 56 seismic records captured in the Pedernales earthquake (April 16, 2016). The response of the isolated systems was compared with the response of the embedded systems based on 3 parameters: displacements relative to the base (basal shear), maximum absolute accelerations (damage in contents), and relative interstory displacements (drift). A high efficiency of the seismic isolation system was observed for structures with few degrees of freedom subjected to high seismic demands. In contrast, isolated systems were found to offer little or no response reduction for systems with many degrees of freedom subjected to light demands. There were cases where isolated systems generated an amplification of the response, this occurred for very small responses resulting from slight earthquakes that would not represent a danger to the structure.