Research On Test And Design Method Of Prefabricated Floor And Cast-in-situ Beam Joints

Today,vigorously promoting the industrialization of housing has led to the rapid development of precast concrete structures,in which prefabricated components have been produced at the factory,the quality of products is excellent,the construction period during operation is significantly shortened,safety accidents are reduced,and environmental protection is conducive to sustainable development.The prefabricated slab cast-in-place beam joints studied by this group has the advantages of simple construction,saving of building materials,and shortening the construction period.At present,the combination of beam and plate joints is mainly composed of cast-in-place concrete beams and cast-in-place concrete slabs.This type of combination has many disadvantages such as complicated construction operation and long period in the construction process,which affects the construction efficiency and construction quality.The beam-plate combination studied in this study is beam-in-place beam,but the plate is prefabricated.The prefabricated panels eliminate the formwork part of the panel,making the construction easy and easy to mass produce.The prefabricated panels eliminate the formwork part of the panel,making the construction easy and easy to mass produce.With prefabricated panels instead of cast-in-place panels,the performance of the joints at the joints of the beams and plates must be verified through research.In this paper,the specimens of beam board joint with beams in the middle are tested.The four beam-slab specimens were tested under static load.Two of the beam-slab specimens were static load tests under normal conditions.Two beam-slab node specimens were caused by uneven settlement on the foundation.The static load test of some extreme cases,such as the sinking of bearings,the low height of beams caused by manufacturing errors,and the breakage of beams and columns,are studied.By comparing and analyzing the test results of each test piece,the differences in the mechanical properties of pre-cast slab cast-in-situ concrete nodes and ordinary cast-in-place concrete girder slab joint were explored.The four beam-slab specimens were tested in a low-cycle repetitive loading mode to investigate the failure modes,hysteretic behavior,component ductility,energy dissipation capacity,and stiffness degradation of cast-in-place beam specimens.Comparing and analyzing the test results,it is found that under the static load that is opposite to the force of the normal beam-plate joints.Precast slab cast-in-situ beam joint specimens are similar to ordinary cast-in-place concrete beam slab joints in terms of overall performanc,ultimate bearing capacity,etc.There are differences in the cracking load and damage morphology between the two.Using the existing formula,the characteristic load of the specimen is calculated,and the cracking load and ultimate bearing capacity are analyzed.Obtain the ultimate load ratio ratio coefficient of ultimate bearing capacity of test specimen and comparative specimen.Under the low cyclic reversed load: Compared with the seismic performance of ordinary cast-in-place concrete beams and slabs,the seismic performance indexes of precast slab cast-in-situ beam joint specimens are slightly lower than those of cast-in-situ slab joints.