RESEARCH ON THE SAFETY OF PERFORMANCE-BASED ISOLATION DESIGN METHOD UNDER STRONG EARTHQUAKE

Design method of isolation is an important part of isolation technology. This paper presents a performance based isolation design method to further disscuss and improve the design method of isolation structure. The structural design response and cost difference based on the design method putted forward in this paper and the traditional isolation design method through engineering example, are compared respectively. The dynamic elastic-plastic time analysis of isolation structure under rare earthquake and extremely rare earthquake are carried out to evaluate the safety. The distribution of damage in structural elements and the damage evolution law of structural units are analyzed based on the indicator (i.e. the ultimate damage indicator of structural elements) obtained by applying the combination of weight. In addition, the safety assessment is evaluated from the angle of energy dissipation and damage evolution. Results show: Compared with traditional isolation design method, the performance objective of performance-based isolation design method is three times higher and the cost is less than one fifth higher. The isolation layer dissipated more seismic energy under strong earthquake, and the superstructure is less damaged. It can completely meet the performance design objectives of "intact after fortification earthquake; can be repaired after rare earthquake; non-collapse after extremely rare earthquake". This method can be used in seismic isolation design.