Study On Shear Mechanism And Mechanical Properties Of Composite Shear Connectors For Steel-Concrete Composite Bridges

In order to make steel-concrete composite bridge have greater bearing capacity and better durability,some scholars,based on the stud shear connector and the perforated steel plate(PBL)connector,start with improving the performance of shear connectors in the structure,and carry out in a more comprehensive way.Therefore,this thesis proposes a composite shear connector with the advantages of stud shear connector and PBL connector,and introduce a Steel-Fiber Composite Bar(SFCB)with excellent corrosion resistance,fatigue resistance and tensile properties as its penetrating reinforcement.By combining theory,experiment and simulation,the shear mechanism and static mechanical properties of the proposed composite shear connector are studied.The main work contents and results are as follows:(1)By collecting and sorting out the relevant literature on the loading mechanism,failure characteristics and influencing factors of the stud connector and the PBL connector,we get the guidance for the subsequent research on the mechanical properties of the composite shear connector.And in this process,the numerical calculation relationship between the shear bearing action and the bending angle of the through reinforcement is deduced.It is found that the through reinforcement mainly relies on its own bending and tensile deformation in the bearing process,which preliminarily proves the feasibility of taking SFCB as the through reinforcement to participate in the shear bearing.(2)By designing and launching the push-out tests of 17 composite shear connector specimens,we get to know the effects of stud arrangement,through reinforcement’s material and number of shear components on the mechanical properties forcomposite shear connectors.Finally,the laws of the force transfer mechanism,bearing capacity and load slip of the composite shear key are obtained.It is concluded that the mechanical properties of composite shear keys are superior to those of the single shear connectors,and the proposed composite shear keys in different arrangements have their own performance advantages and application ranges.(3)Establish all the specimens’ finite element model in the test to further clarify the stress of each shear component in the composite connector under the shear load.And a more accurate force transfer mechanism of composite shear bond is obtained,which proves the feasibility of SFCB composite reinforcement used as a shear member to carry the load.(4)According to the results of test and finite element analysis,the superposition method was adopted to establish the formula for calculating the shear bearing capacity of the composite shear connector,during which the reliability coefficient was introduced and solved.The results show that the difference between the calculated values and the experimental values is small.The formulas obtained can be used to predict the bearing capacity for the same type of composite shear connectors.