Experimental Study On Forms Of Assembled Concrete Joints And Collapse Resistance Of Beam-Column Structures

With the vigorous pursuit of industrial development in China,various types of joint-type assembled concrete structures have sprung up,in which the assembled monolithic and fully assembled structures occupy the main position.Whether these two structures can maintain stability under accidental loads and how to improve their collapse resistance are worth studying.Therefore,this paper takes the assembled integral and fully assembled beam-column structure as the research object,through dismantling the quasi-static loading mode of the mid-column,and on the basis of the collapse resistance test data of the east-in-place structure,studies the stress mechanism of the assembled integral and fully assembled beam-column structure,and uses Opensees finite element software to analyze the collapse mechanism.This paper mainly carries out the following work and research:(1)Based on the research purpose,two different types of beam-to-column connections are designed,which are assembled monolithic keyway beam-to-column joints and bolted fully assembled beam-to-column joints.These two types of joints provide support for the following experimental study on collapse resistance of assembled beam-to-column structures.(2)Static loading tests of 5 1/2 scale single-storey two-span beam-column structures have been completed.Three of them are monolithic reinforced concrete beam-column structures with keyway joints and the other two are fully assembled reinforced concrete beam-column structures with bolted connections.The load-displacement curve,collapse failure pattern,crack development and strain change of beam-column structure under collapse load are obtained,which provide data support for the following analysis of collapse resistance of beam-column structure.(3)By comparing the test results of beam-column structures with different ductile overlapped bottom bars and different ductile post-poured concrete keyway joints,the effects of high ductile overlapped bottom bars and high ductile concrete at joints on collapse performance and stress mechanism of structures are studied.By comparing the test results of beam-column structures with keyway joints,bolted joints and east-in-place joints,the collapse resistance of beam-column structures with different connection joints based on "equivalent bearing capacity" is evaluated.(4)Based on the idea of "equal in-situ pouring",a numerical model of cast-in-situ structure using beam-column joint element is established by using Opensees finite element software,and the influence of bond-slip ability of steel bars on the mechanical mechanism of structure is studied.Based on the law of energy conservation,a method for evaluating the collapse resistance of structure considering dynamic effect is proposed,which provides a basis for collapse resistance design.