Progressive Collapse Resistance Of ECC-reinforced Concrete Composite Beam-column Sub-assemblages

Under the action of accidental loads such as fire and explosion,reinforced concrete frame structures may cause continuous collapse and damage,which seriously threatens the wealth and safety of the users.Therefore,in the structural design of the world,more and more attention has been paid to improving the continuous collapse resistance of structures.Compared with ordinary concrete,ECC has the advantages of high ductility and ultra-high toughness,as well as excellent crack control ability.Therefore,the use of ECC to improve the progressive collapse resistance of beam-column sub-assemblages under extreme load and large deformation has a broad development prospect in the study of the progressive collapse resistance of frame structures.In this paper,experimental research and finite element analysis are carried out on the performance of ECC-RC composite beam-column sub-assemblages against progressive collapse.The main work includes:By using ECC material to replace ordinary concrete of different height and position,six specimens of different beam column structures are made,and six specimens are tested for resistance of progressive collapse.The test data of different specimens,such as failure mode,vertical displacement-load curve of middle joint,axial force curve of beam,distribution of concrete cracks,development of stress and strain of reinforcement,are compared and analyzed.The effects of different height of ECC material at the bottom of the beam,ECC material at the different positions of beam and enhancing the concrete strength on the progressive collapse resistance of beam column sub-assemblages are studied and compared.Using MSC.Marc finite element simulation software,the beam column structure model in the test is established,the nonlinear calculation and analysis of the whole process of progressive collapse resistance are carried out,and the load displacement curves and failure positions of different specimens are obtained,and the simulation results are compared with the test data.According to the different reinforcement methods of beam-column sub-assemblages,the bearing capacity calculation formula of the specimens in three stages of beam action,compressive arch action and catenary action is deduced.Compared with the test data and simulation calculation results,the calculation formula suitable for the structure applying ECC is obtained.