Equivalent linearization analysis method for seismic isolation structures based on GB / T 51408―2021 “Standard for seismic isolation design of buildings”

In order to clarify the displacement estimation accuracy of the current equivalent linearization analysis method for isolation structures‚ displacement calculation results from 1000 single degree of freedom isolation models were analyzed by using the conventional equivalent stiffness and equivalent damping ratio. The analysis was based on the acceleration response spectrum of the GB / T 51408―2021 “Standard for seismic isolation design of buildings” (hereinafter referred to as the “Isolation standard”)‚ and the results were compared with the dynamic elastic-plastic analysis results. The results show that when conventional equivalent parameter calculation methods are used in combination with the isolation standard for equivalent linearization analysis‚ the calculation results of isolation bearing displacement are larger‚ the statistical values approximately follow a normal distribution‚ with a mean of approximately 1. 5. In order to improve the accuracy of the equivalent linearization analysis based on the isolation standard‚ an equivalent period and equivalent damping ratio calculation formula was proposed. By analyzing three models of isolated structures‚ it is verified that this formula can reasonably calculate the displacement of the bearing of isolated structures‚ but tends to overestimate the bearing force. Therefore‚ a revised formula for predicting seismic response was proposed. By comparing with the dynamic elastoplastic analysis results‚ it is shown that the shear force at the bottom of the modified isolated structures is close to the time-course analysis results‚ and the error can be controlled within 20% . © 2023 Science Press. All rights reserved.