Study On Mechanical Behavior Of Novel Joint Of Pre-fabricated Concrete Floor

With the rapid development of the construction industry,the state has issued policies related to prefabricated buildings in recent years,and prefabricated building structures account for an increasing proportion in engineering.In order to meet the requirements of some building quality or be restricted by transportation conditions,the size of prefabricated floor slabs is often not too large during production in prefabricated factories,resulting in the need for joints between prefabricated floor slabs.However,the mechanical performance of the joint between the joints is relatively complicated,and it is generally a relatively weak place in the structure,so it is very important to study a reasonable joint method.In this paper,the mechanical properties of fully prefabricated ring-connected floor slabs are tested and the mechanical properties of fully prefabricated floor supporting steel corbels are tested.At present,prefabricated floor slabs mostly appear in the form of integral assembly,but this form still has a large part of wet work on the construction site,and requires a large number of formwork and scaffolding support systems,and the construction efficiency is low.Therefore,researching and promoting the form of prefabricated floor slabs that can improve efficiency and quality has become an urgent problem in prefabricated buildings.This paper analyzes the performance of the fully assembled floor slab system by testing the mechanical properties of the fully prefabricated buckle plate seam connecting the floor slab and the fully prefabricated floor slab supporting steel tongue and groove.First of all,in order to study the mechanical properties of fully prefabricated ring-connected floor slab joints,a comparative test was carried out on three fully prefabricated ring-connected floor slabs in actual projects to verify the effectiveness of the ring-connected slab joints;Designed and completed five fully prefabricated ring-connected floor slabs and conducted a concentrated load test.By comparing and analyzing the load-deflection curve,load-reinforcement strain curve and crack development distribution of the specimen,the arrangement of ring reinforcement,the width of the plate joint,The effect of the diameter of the middle insert bar and the type of rough surface of the post-casting section on the stiffness,bearing capacity and deformation of the specimen.Secondly,six fully prefabricated floor slabs with steel tongue-and-groove supports were designed.Through shear tests on the supporting steel tongue-and-groove nodes,the load-deflection curve,load-reinforcing steel strain curve and crack development distribution of the test specimen were compared and analyzed.To study the influence of the stirrup ratio,the location of the hanger bar,the wall thickness of the square steel tube,and the joint form on the mechanical performance of the tongue and groove joint.The results show that the specimen mainly has three failure modes: shear failure of the protruding end of the steel pipe,local pressure instability failure of the abdomen of the protruding end of the steel pipe,and failure due to insufficient tensile bearing capacity of the hanger;The bearing capacity of the form and the form of hanging bars near the top of the board has been improved to a certain extent,and the performance of the material can be fully exerted.Finally,the finite element software ABAQUS was used to perform a numerical simulation on the fully prefabricated ring-connected floor slab.By comparing and analyzing the simulation results and the test results,the validity of the finite element model was verified,and on this basis,the diameter of the insert bar and the middle were changed.The parameters of slab width and pre-embedded ring reinforcement ratio were analyzed to analyze the influence on the mechanical performance of the joint of the floor slab,which provided a reference for the design and application of fully prefabricated ring slabs.