Research And Optimization On Seismic Performance Of Steel-concrete Composite Frame-core Tube Structural Systems

As composite frame-core tube system has been adapted widely in our country,the seismic performance of this system is very important,and this paper has conduct research on this aspect.The main research done in this paper includes propose efficient analytical method and comparative parameter,conduct elastic-plastic analysis on the systems by several parameters,indicate new design ideas and study the performance of new connector used in composite structure.The main research works conducted in this paper are as follows:An efficient analytical method on seismic performance of composite frame-core tube system has been proposed.Based on finite element program and fomer research result,an efficient analytical method on seismic performance of composite frame-core tube system has been proposed.Using this method,elastic-plastic behavior of the composite component can be simulated under large seismic load with low computational cost and high accuracy.The method to definite equivalent lateral stiffness of composite frame-core tube system is proposed by finite element method.The whole structural lateral stiffness is derived by combining theory and finite element methods,under several types of loads including inverted triangle load,top load,even load and random load.This method can be used to definite lateral stiffness,as an important parameter in design stage.Elastic-plastic time-history analysis of whole composite frame-core tube system is conducted by incremental dynamic analysis method,to study optimization direction of this system.By using efficient analytical method and equivalent lateral stiffness proposed in this paper,elastic-plastic time-history analysis of whole composite frame-core tube system is conducted.The performance curves of each structure and shear-baring ratio regularity have been studied.Further more,new conceptions of high performance composite frame-core tube system are proposed,from several aspects,including design idea,design method and local parameter.A new type of uplift-restricted and slip-permitted T-shape(URSP-T)connector is proposed to improve mechanical performance of the hogging moment region in composite beams.In order to investigate the slip and uplift performance of URSP-T connectors,six push-out tests,three pull-out tests and three interface tests are conducted.Based on test results,the relationship between uplift performance and dimensions of connectors is discussed.Meanwhile,finite element analysis proves that URSP-T connectors permit larger slip deformation and reduce tensile stress inside concrete in the hogging moment region of composite beams.Investigation in this paper may provide basis for design and application of URSP-T connectors.