Study On The Flexural Behavior Of Steel-concrete Composite Beams Based On The Shear Performance Of Headed Stud Connectors

The mechanical properties of steel-concrete composite structures are not only affected by the properties of steel and concrete materials,but also have an important relationship with the shear connectors.With the advantages of excellent mechanical properties and construction performance,stud connectors are widely used in steel-concrete composite beams.In this research,we systematically investigated the factors such as concrete strength,stud diameter and stud height on the shear performance of stud connectors and the flexural performance of composite beams,using three methods of push-out test,beam test and finite element analysis.The main research contents are as follows:(1)In order to study the shear failure mechanism of stud connectors,static push-out tests were carried out on 3 groups of 7 specimens and the damage pattern and crack development of each specimen were compared and analyzed.According to the measured load-slip curves,the mechanical characteristics of the shear bearing capacity,shear stiffness,peak slip were obtained,and the variation laws of the parameters such as concrete strength,stud diameter and stud height were investigated,and compared with the theoretical formulas proposed by relevant domestic and foreign codes or scholars.The results show that the three parameters have significant effects on the shear performance of the stud connectors.(2)In order to explore the flexural behavior of steel-concrete composite beam connected with studs,a steel-concrete composite beam was made of the same material as the C40D16L60 specimen,The monotonic static loading test of symmetrical two points in the middle of the span was carried out.Based on the measurement results,the load-deflection curves,the loadslip distribution curves along the length of the beam and the load-strain curves of the steel beam and concrete at typical locations were obtained,and the bending failure mechanism was investigated in conjunction with the damage process of the composite beam.(3)In view of the limitations of experimental research methods,in order to further improve the influence of stud connectors on the bending performance of composite beams,based on the push-out tests and the composite beam test,Midas FEA NX software was used to establish and verify the finite element model of the composite beam.By changing the model parameters,the calculation results of the composite beams were obtained for different variables such as the number of studs,concrete strength and stud specifications,and the influence law of various parameters on the mechanical performance of the composite beams were analyzed.The results show that the number of studs had a great influence on the flexural behavior of composite beams.The concrete strength contributed to the load carrying capacity of the composite beam but in a small way.The specifications of the studs had little effect on the flexural behavior of the composite beams within the scope of this paper.