Research On Launching Test And Bearing Capacity Calculation Of New Semi-rigid Shear Connector

Shear connectors are essential to ensure the integrity of steel and concrete assembly type structure or combination of structure,traditional rigid shear just oversized,resulting in poor deformation capacity;and flexible shear has the problem of insufficient load carrying capacity.In response to this situation,this paper proposes a new semi-rigid shear-resistant joint,which aims to achieve effective unification of load-bearing capacity and deformation capacity。A new type of semi-rigid shear-resistant connection is proposed,which aims to achieve effective unification of load-bearing capacity and deformation capacity.Through the monotonic push-out test,the bonding slip performance test of 11 shear parts,revealing the damage process and the force mechanism of the shear parts,and evaluating the performance indexes of the load-bearing capacity,deformation capacity,stress distribution,etc.The influence of different forms of shear resistance,different grouting materials,and whether or not reinforcement is inserted at the opening against the performance of the shear is discussed.On the basis of the test,numerical simulation was carried out,and the influence of the shear aperture diameter,shear folding thickness,folding height and other anti-shear force performance laws were discussed.Finally,a study of the limit load-bearing capacity calculations has been carried out and recommendations for structural design have been given;the following conclusions have been drawn:(1)Concrete slab damage usually forms a main crack along the length of the shear,and spreads around as the load increases,intersecting with the main crack to form a series of cracks。Shear damage is mainly for the middle position of the web plate at the slight bending phenomenon,compared with the staple shear,the overall performance of the new shear is better,a greater range of constraints on the concrete panel,the stronger the embedded role.The strain of the shear is mainly concentrated in the lower middle of the web,and the strain of the rest is smaller.The load-bearing formula proposed according to the analysis of the force mechanism is in good agreement with the test results.Both types of shear resistance have a significantly higher ultimate load carrying capacity and deformation margin compared to conventional pegs.(2)Through the numerical simulation found that,with the shear folding plate thickness increased by 1mm,the limit of the shear bearing capacity increased by about 15%;when the height of the shear increased by 10mm,the limit of the bearing capacity reduced by about 20%,reduce the height of the shear,the bearing capacity increased accordingly,reduce the height of the shear is conducive to improving the bearing capacity of the shear.(3)Based on the experimental and numerical analysis results,recommendations are given for the design of shear resistant parts.Shear resistance type 1 comprehensive performance is better,in the actual engineering application is recommended to be used first;taking into account the shear and floor integrity problems,it is recommended that the height of the shearl/2 to 2/3 thickness of floor slab;considering the combination with concrete,the size of the hole is recommended to 1.5 times the maximum particle size of coarse aggregate;filler is recommended to choose high-strength grout and other high-strength materials,if the choice of commercial mix,should be one grade higher than the floor concrete grade.