| The steel-concrete composite structure can get the full advantages of steel and concrete,and it has been widely used in practical engineering.The shear stud is a key component in the steel-concrete composite structure,and its mechanical properties directly affect the overall performance of the composite structure.There are many researches on the mechanical properties of shear studs,but the emergence of new structures and new materials presents a new problem for the existing theory of shear studs.The main structure of viaduct works in Xiangfu Road quick change project is multi prefabricated steel-concrete composite beam.There are two layers of concrete slabs,the lower part is prefabricated concrete slab,connected with the I-shaped steel beam to form a single main beam,lifting as a template for the upper concrete,the upper concrete directly pouring on the lower concrete slab.Corresponding to the two-layers concrete slab,the composite bridge adopts the group stud connectors with two different length and diameter.The kind of shear stud in the application of the project is the first time.The study of its mechanical properties is of great theoretical significance,which has an important effect on the development of such prefabricated bridges.In this paper,the shear performance of the group stud connectors with two different length and diameter are analyzed by carrying out the experimental study and the finite element analysis based on the steel-concrete composite plate girder bridge in the Xiangfu Road quick change project.The main achievements are as follows:(1)According to the actual engineering background,the purpose of the study,the test conditions,etc.,18 shear stud push-out specimens were designed and manufactured,and the push-out test was carried out,and the failure modes of all the tested specimens were obtained.And the load-slip curve,the influence of the length and diameter of the shear studs on the shear performance of the group stud connectors with different length and diameter were acquired.(2)Considering the nonlinearity of concrete,shear stud,steel beam and steel bar,a refined finite element model is established.First,the results are compared with the experimental results.The results show that the finite element model can simulate the shear test well.The influence of shear stud length,diameter,concrete strength,stud strength,relative arrangement of shear studs and the thickness of concrete slab on the shear performance of group connectors stud with different length and diameter has been analyzed by using the validated finite element model.(3)The length of the shear studs,relative arrangement of the shear studs and the thickness of slab have little or no effect on the ultimate bearing capacity and stiffness of the group stud connectors with different length and diameter.The diameter of the shear nails and the strength of the concrete have a significant impact on the ultimate bearing capacity and stiffness of group stud connectors with different length and diameter.The increase of diameter and strength of the stud and the increase of concrete strength will increase the ultimate bearing capacity and stiffness of the group stud connectors with different length and diameter,and vice versa will reduce the ultimate bearing capacity and stiffness.An empirical formula has been proposed to calculate the shear strength of the group stud connectors with different length and diameter.An expression of load-slip relationship has been proposed. |
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