Study on Seismic Safety Evaluation Models for Gravity Dams Based on Integrated Performance Indicators

Existing studies typically explore the differences in seismic performance evaluation results of different evaluation models for concrete gravity dams by analyzing amplitude factors while neglecting the influence of ground motion duration. As a result, the influence of different evaluation models on the seismic performance of gravity dams can not be evaluated comprehensively. This paper, using the efficacy coefficient method, integrated the overall damage index of the dam body and the relative displacement of the dam crest to construct a comprehensive seismic damage evaluation model for gravity dams. Taking the Koyna gravity dam as the research subject, this paper examined the influence of ground motions with different strong seismic motion durations on the seismic damage degree of the dam body under both single-indicator and multi-indicator evaluation models, and the analysis results of different evaluation models on the seismic performance of gravity dams were compared. The result indicates that ground motion duration is positively correlated with the damage degree of gravity dams, and relying on a single evaluation indicator may lead to conservative or dangerous evaluations of the damage degree of dam bodies. A comprehensive evaluation model can more accurately reflect the influence of variations in strong seismic motion duration on the damage degree of concrete gravity dams.