Mechanical Properties Of Composite Shear Connectors For Steel-fiber Ceramsite Concrete Composite Beams

With the rapid development of society,bridge construction is advancing at an unprecedented speed.The steel-concrete composite structure has the characteristics of concrete and steel structure,which makes it have a wide range of application prospects in bridge construction,and the lightweight characteristics of lightweight aggregate concrete provide conditions for the application of composite structure in long-span bridges.In the composite structure,the suitable shear connector can make the steel structure and concrete fully function.In this paper,the mechanical properties of stud shear key,PBL shear key and composite shear key in fiber reinforced ordinary concrete and fiber ceramsite concrete are studied respectively.The research contents and main conclusions are as follows:(1)A new form of shear connector named composite shear connector is proposed,and its rationality and related mechanical properties are analyzed and tested.(2)10 push-out test pieces of PBL shear key,stud shear key and combined shear key were designed and fabricated,and the static tests were carried out.The mechanical properties,failure modes,load-slip laws,load stress laws of shear keys and so on in two types of concrete are obtained.The test results show that the bearing capacity of the composite shear key push-out test pieces is much larger than that of the other two kinds of shear key push-out test pieces,and the interfacial slip effect of the composite shear key push-out test pieces is smaller than that of the stud shear key push-out test pieces and is equivalent to that of the PBL shear key push-out test pieces.The test piece of the same kind of shear key has a lifting effect and interfacial slip in the lightweight aggregate concrete which is more serious than ordinary concrete.(3)The finite element model corresponding to the three shear keys is established and its parameters are selected according to the test results.The finite element analysis results are compared with the test results,and the results show that the test results are in good agreement with the finite element analysis results.(4)According to the existing research and results of the test,the calculation formulas for the bearing capacity of the test piece and the bearing capacity of the composite shear keys in the test are established.