Study On Seismic Behavior Of The Resilient RC Frame Structures Based On C Shell Members

The post-earthquake resilience becomes a new index to measure the seismic performance of structures.After the earthquake in the city,the loss of secondary disasters far exceed the earthquake itself.Rapid restoration of building functions has become a new research direction in the field of earthquake resistance.RC frame structures provide great applicability in the layout of building functions,for most public buildings,such as schools,shopping malls,hospitals,etc.They need a large space in the bottom,and the superstructure has dense packed walls with high rigidity.The previous earthquake indicated that such structures tend to be damaged by concrete end,and the damage of superstructure is light.In view of the obvious weak story structure,a resilient structure system with C shell members was proposed and arranged them at the bottom of the structure where the earthquake damage is concentrated.C shell members support the structure temporarily after the earthquake,at the same time the damaged concrete column can be repaired quickly to make the RC frame structure have resilient performance.The main work is as follows:(1)The basic mechanical properties of C shell members were explored,including the lateral bearing capacity and the vertical bearing capacity after large lateral deformation,to verify whether it can support the superstructure after a big earthquake.The test results show that the bearing capacity of C shell members has no obvious attenuation after multiple lateral loads,and it has good resilient performance.The axial compression test after large lateral deformation shows that the C shell members still have the vertical bearing capacity.The effects of different geometric factors on the lateral and axial compressive buckling loads of C shell members were studied,and the corresponding buckling load formula was fitted.(2)Three kinds of RC frame structure models with different bottom height were designed to carry out earthquake simulating shaking table test.The seismic damages of the three RC frame structure models with different bottom height were compared under different working conditions.According to the test results,the damage of a height of3.3m model is obviously concentrated in the bottom story.The resilient structures were set at the bottom of the model and compared shaking table test results in the same working condition to get their effect on the RC frame structure.(3)After the nine-degree rare earthquake the inter-story displacement of bottom story of resilient RC frame structure has exceeded the limit,but the C shell members replace the damaged concrete column to support the superstructure.A shaking table test was carried out on the independent support model of C shell members to verify the postearthquake safety performance of the resilient structural system.The test results show that the resilient system with C shell members can support the superstructure safely and effectively without buckling when the inter-story displacement angle reaches 1/17.At the same time,replacing the bottom pillar can realize the rapid recovery of structural functions.(4)ABAQUS software was used to build the concrete frame model with fiber rod element,and FQ-FIBER subroutine developed by Tsinghua University was used to analyze the dynamic elastoplastic of the model.Compared with the test results,the failure conditions of each model under different working conditions are basically consistent with the test results,verifying the reliability of finite element simulation method and model vibration table test.