Research On The Mechanical Properties Of Stud Shear Connectors With Constrained Structure

The steel-concrete composite structure is a new type of structure developed on the basis of steel structure and reinforced concrete structure.It is connected as a whole through the shear joints,and can be combined with force and deformation.The shear connection is a key connecting component that realizes the joint action of the steel beam and the concrete slab.Its main function is to transmit the longitudinal shear force between the steel beam and the concrete slab and resist the relative slip and vertical direction between the two.The cockroach works so that it can be tightly combined and force together.Because the stud connection is characterized by strong deformation ability,non-directional force and convenient construction,it has become the most commonly used shear connection for steel-concrete composite beam structures.In order to further study the stud shear joints that can restrain the concrete splitting and splitting development,as well as the effective elastic bearing capacity of the new shear joints,and to verify the high efficiency of the new shear joints against cracking,In this paper,five different types of test pieces and one comparative test piece were designed to carry out the experimental research.The experiment proved the excellent anti-cracking mechanical properties of the new shear joints.According to the experimental data and the observation of the whole process experiment phenomenon,The mechanical properties of the new shear connectors and the traditional stud connectors are fully compared.The main work and research results are as follows:(1)The test piece of five different diameters of the peg shear connection with the restraint structure and one conventional peg shear connection were introduced to carry out the static push-loading test.The test results show that the stud shear connection with constrained structure can completely avoid the local pressure damage caused by the “cutting” pressure of the stud shear connection and the effective elastic shear load capacity.Stable and reliable stud connection stiffness.The test data were sorted to obtain the load-slip curve of each test piece.It was found that the initial stiffness of the extruded test piece with restraint structure was much higher than that of the traditional test piece,and the interface was bonded with the increase of slip.As the strength increases,the shear stiffness reduction rate of the constrained test piece is very slow.(2)The load-slip curves of each test piece were obtained by launching the test piece.It was found that the initial line elastic stiffness of the stud shear connection with constrained structure was stronger than that of the traditionally launched test piece,and with the increase of slip.The shear stiffness is linear elastic force,the bond strength of the interface is increased,and the shear stiffness reduction rate of the constrained structural specimen is very slow.(3)The restraining structure of the stud shear connection with constrained structure can effectively avoid the splitting of the seesaw until the stud is cut or the seesaw is crushed,and the flange plate has no cracking damage at all.The stud shear connection with the constrained construction can transmit the shear force more effectively between the steel-concrete interfaces,so that the two work together better,and the compressive bearing capacity of the flanged flange and the stud are sheared.The proportional relationship of the bearing capacity is used to control the different failure modes,so that the composite members do not break the shear connectors of the composite members before the compression of the composite members(or before the tensile stress of the steel plates in the tension zone).(4)In order to be unified with the domestic calculation norms,a correction coefficient is proposed to calculate the ultimate shear capacity of the stud connection with constrained structure.According to the test results,the expression of the stud stiffness is obtained.