Seismic Isolation Performance Analysis Of RC Frame Structure Under Pulse-like Earthquake

The obvious long-period velocity and displacement pulse motion of pulse-like earthquake may have an adverse effect on the seismic performance and design of the seismic isolation structure.In order to prevent the damage of buildings by pulse-like ground motion,this article is based on the engineering example in Hanzhong area,Shaanxi Province.The SAP2000 finite element analysis software established an 11-story RC frame structure model,and optimized the seismic isolation structure of the RC frame structure.Through modal analysis and linear time history analysis,study the natural vibration characteristics and elastic deformation capacity of RC frame structure and seismic isolation structure;focus on the impulse ground motion parameters in Hanzhong area,and study the impulse through nonlinear time history analysis and Pushover analysis.The elastoplastic deformation capacity,overall anti-side displacement ability,seismic energy dissipation capacity and structural performance point parameter changes of RC frame isolation structure under the action of type ground motion.The main conclusions are as follows:（1）After extracting the seismic influence coefficients of pulse-like ground motion Coyote Lake,San Salvador,and Westmorland,and comparing them with the maximum influence coefficient of horizontal earthquakes in Hanzhong area,it is found that the seismic influence coefficients of the three impulse seismic waves are the average seismic fortification about twice the earthquake.（2）Through the analysis of the time history of the RC frame base isolation structure and the story isolation structure under the fortified earthquake,it can be seen that the elastic deformation of the base isolation structure and the story isolation structure in the X and Y directions is greatly reduced compared with the RC frame structure.And,the degree of reduction of the layer-isolated structure is slightly smaller than that of the base-isolated structure.（3）Through the pulse-like ground motions downtime analysis of the RC frame structure,the base isolation structure and the layer-isolated structure,it can be seen that the RC frame structure,the base isolation structure and the layer-isolated structure are structured in the X and Y directions under pulse-type ground motions.The overall deformation degree is much greater than the seismic fortification ground motion;the two types of seismic isolation structures have relatively small overall deformations relative to the original structure,which reflects a good damping effect,and the base isolation damping effect is better than that of the story isolation structure.（4）Through the pulse-like ground motions downtime analysis of the RC frame structure,the base isolation structure and the layer-isolated structure,it can be seen that the RC frame structure,the base isolation structure and the layer-isolated structure are structured in the X and Y directions under pulse-like ground motions.The overall deformation degree is much greater than the seismic fortification ground motion;the two types of seismic isolation structures have relatively small overall deformations relative to the original structure,which reflects a good damping effect,and the base isolation damping effect is better than that of the story isolation structure.（5）Through the analysis of the inter-story shear force and the seismic wave energy dissipation analysis of the base isolation structure and the story isolation under the pulse-like ground motion,it can be seen that the interstory shear force of the RC frame structure is greatly increased under the action of the base isolation and the story isolation.The reduction of the shear force between layers of the base isolation structure is greater than that of the layer isolation structure;through the analysis of the absorption and dissipation of pulse-like ground motions by the two types of isolation structures,the seismic wave energy dissipation capacity of the base isolation structure is stronger than that of the layer interval,Therefore,the base isolation structure is the best isolation design scheme.（6）Through the Pushover analysis of the RC frame base isolation scheme under impulse ground motions,the results show that the original structure performance point parameters under impulse ground motions are relatively high,the distribution of plastic hinges is very dense,and there are multiple plastic hinges at the end of the column and impulse earthquakes.Dynamic damage to the RC frame structure is extremely great;the performance point parameters of the base isolation structure under pulse-like ground motions are significantly reduced compared to the original structure,and the plastic hinge out rate is greatly reduced.There is no column end plastic hinge at each node,indicating that the base isolation structure has good damping effect.