Experimental And Theoretical Study On Flexural Resistance Of Recyclable Fully Assembled Steel-concrete Composite Beams

At present,as the representative of a new round of scientific and technological revolution in the construction industry and the direction of industrial change,prefabricated building has ushered in a precious period of historical opportunity.But at the same time of full confidence in the future,we should also clearly see that the development of prefabricated building is still facing many problems.In the field of composite beam,it is difficult for the existing prefabricated composite beam scheme to realize full assembly construction and disassembly recycling.In recent years,many researchers continue to make efforts in order to make breakthroughs and achieve sustainable development.In this paper,a new type of fully assembled steel-concrete composite beam with bowl shaped connectors,pre embedded C-type steel guide channel precast floor,steel beam and TJ type shear connectors can meet this requirement.This kind of recyclable fully assembled composite beam realizes full dry connection,disassembly and partial recycling.In order to study the flexural performance of the recycled fully assembled steel-concrete composite beam,six full-scale four-point bending tests were carried out to study the failure mode,load deflection curve,relative slip distribution,strain change of TJ shear connector and modal change of the composite beam.The effects of the length of pure bending section and the number of precast slabs on the flexural stiffness were discussed and bending capacity.The test results show that when the composite beam reaches the limit state of mid span deflection of L/50,the deformation of the bowl connector and shear connector are in the elastic range,which meets the requirements of cyclic use;five groups of fully assembled composite beams show partial combined action,and TJ type shear connector significantly improves the bending stiffness and bending capacity of the steel beam.Secondly,ABAQUS finite element software is used to model and analyze the composite beam,and the results are compared with the experimental results of recyclable fully assembled steel-concrete composite beams to verify the accuracy of the finite element model.Furthermore,the influence of pure bending length and TJ type shear connector preload on the mechanical performance of composite beams is explored.Finally,based on the test results and finite element simulation results,the design method of this type of composite beam is proposed,including the deflection calculation formula and the ultimate bending capacity calculation formula of the composite beam in the elastic stage.The deflection value and bending capacity obtained by this method are in good agreement with the test results,which can be used as the design basis of the composite beam.