Global damage model for the seismic reliability analysis of a base‐isolated structure

A method for seismic reliability analysis based on a global damage model is proposed for a base-isolated structure. A sample space is created using the Latin Hypercube Sampling method, in which the randomness of structure and seismic ground motions is considered, and then dynamic elastic–plastic analysis is carried out for each sample. The cumulative damage factors of the upper structure and the isolated story are calculated using a global damage model of an isolated structure. The probability of progressive sideway collapse for base-isolated structure under earthquake action is obtained using the quadratic fourth-moment method, and this method is also used to analyze the evolution of the probability density of cumulative damage for structure. From aforementioned analysis, the change tendency of damage factor over time can be obtained using the global seismic damage model based on the quadratic fourth-moment method. Due to the introduction of the quadratic fourth-moment method in this paper, the impacts of skewness coefficient and kurtosis coefficient on the failure probability of structure can be taken into account, if the scheme of a structural parameter cannot be confirmed. The method provides results that are more accurate than those of the classical first-order second-moment method. A method for the seismic reliability analysis of an isolated structure from the component to the global structure is also established, in which the failure probabilities of the upper structure and the isolated story are considered with a global seismic damage model.