Study On Impact Performance Of Beam-to-column Composite Joints In Steel Frame Structures

At present, both national and foreign scholars have conducted extensiveresearches on the progressive collapse of structures, many countries have drawnup relative specifications to prevent progressive collapse of structures, puttingforward some specific design methods. In steel frame structure, beam-to-columnjoints, as a key component for power transmission, having large deformation inthe process of collapse prevention. Constrainted by concrete slabs at the sametime, the concrete slabs have a certain influence on the collapse of structures. Inthis paper, the stress of beam-to-column composite joints and the shearconnection performance of studs between concrete slabs and steel beams werestudied. By using the drop hammer tester of Hunan University, twobeam-to-column composite joints and fourteen push-out specimens were tested.The nonlinear FEA software ABAQUS were used to build models about the studconnectors in composite beams and beam-to-column composite joints, makingdeep analysis on the mechanical performance of stud connectors and compositejoints. The main job of the paper is as follows:(1) On the basis of the completed beam-to-column joints tests, twobeam-to-column composite joints were designed according to relevantspecifications, considering two connection types, Welded-Flange-Bolted-Webconnections and Bolt Unstiffened End Plate connections. Fourteen push-outspecimens were designed according to the standard push-out specimens of ECCS,considering concrete strength and impact energy.(2) The static and impact tests about the research on the shear capacity ofstuds were carried out, and the influence of concrete strength and stain rate onfailure mode of specimens, shear capacity and slip resistance of studs werestudied, and dynamic response of studs were studied by analyzing test results.(3) The impact test of beam-to-column composite joints were carried out,which focuses on the failure modes, bearing capacity and deformability of thespecimens. By comparing with the test results of beam-to-column joints, theinfluence on the stress of the joints caused by concrete slabs were analyzed.(4) The FE software ABAQUS were used to build models about the sheartests of studs, the failure mode of specimens, shear capacity and slip resistance of shuds in static and impact tests were obtained, the simulated results have a goodagreement with the test results.(5) The FE software ABAQUS were used to build models about the tests ofbeam-to-column composite joints, the deformation modes, bearing capacity, thedisplacement of midspan and internal force of the cross section of compositejoints were obtained. The models without concrete slabs were built, the effects ofconcrete slabs on mechanical performance of joints were obtained bycomparative analysis.