Dynamic Response Analysis Of Base Isolated Structure Based On Displacement Target Design

The traditional force based isolation design method can not achieve the preset isolation goal,and the displacement index of the structure is not clear enough.The direct displacement based design method is a mainstream performance-based design method,which can effectively control the damage condition and deformation ability of the structure under the earthquake action,and avoid large economic loss.Therefore,in this paper,LRB lead rubber base isolation structure is designed from a new direct displacement based design point of view,so that it can meet the performance index corresponding to the target displacement,and compared with the traditional force based isolation design and non isolation design;through the nonlinear time history analysis,it is verified whether the direct displacement based isolation design matches the target performance,and whether the direct displacement based isolation design matches the target performance Achieve the goal of performance design.The research contents are as follows:1.The principle and basic steps of direct displacement based seismic design method(ddbd)for conventional non isolated building structures are described.A new concept of direct displacement based seismic design is applied to the process of base isolation design.Based on the analysis of dynamic characteristics and seismic response of the equivalent model of two degrees of freedom(2DOF),a kind of integration of isolation layer and superstructure is established Equivalent substitution model of displacement relation of structural characteristics.2.Taking LRB lead rubber base isolation structure as the calculation and analysis model,the horizontal displacement limit of LRB Isolation Bearing and the inter story displacement angle of upper structure are calculated according to the fortification level,following the basic ddbd steps,and combining with 2DOF model,the base shear force and relevant isolation parameters of LRB base isolation structure are calculated.3.SAP2000 is applied to build the model of the above-mentioned isolated frame structure,and the horizontal seismic force obtained based on the displacement design method under the action of fortification earthquake is applied to the upper structure,and the reinforcement design is carried out for the upper structure.When the load is combined,the partial coefficient of seismic action,the partial coefficient of material and the adjustment coefficient of seismic bearing capacity are applied when the value is 1.0,the material strength is taken as the standard value when checking the bearing capacity of the component;based on the software ETABS,ddbd can be compared with the results of traditional force based isolation design and non isolation design,and it can be concluded that the isolation effect of direct displacement based isolation design method is more obvious than that of traditional force based isolation design method,which can effectively restrain the displacement deformation of the upper structure and meet the goal of performance-based design.4.Based on simqke,seismomatch and other software,the artificial seismic wave matching the target response spectrum is generated.In SAP2000 finite element software,the structure model considering the isolation element is established,and the nonlinear time history analysis of the isolation structure is carried out by loading the artificial seismic wave.The results show that the performance indexes of displacement and inter story displacement angle meet the preset target performance requirements.