Study On Mechanical Properties Of Lightweight Aggregate Concrete Stud Connectors

At present,stud connectors are the most widely used,but there are many gaps and deficiencies in the research results of lightweight aggregate concrete stud connectors,which become the obstacles to the application of steel-lightweight aggregate concrete composite structures in practical projects.In this paper,the mechanical properties of lightweight aggregate concrete stud connectors are systematically studied by means of extrusion test and finite element numerical simulation.A total of 6 groups of 12 pushout specimens were designed according to the four influencing factors of concrete type,concrete strength,stud diameter and stirrup arrangement.The failure mode,load-slip curve,shear bearing capacity,shear stiffness and peak slip of these specimens were analyzed.According to the test results,the ultimate tensile strength of the stud was added and the original influencing factors were expanded.According to the five influencing factors,15 models were established for finite element numerical simulation analysis,and the shear capacity and shear stiffness of the stud were analyzed according to the results.The main conclusions of this paper are as follows:(1)In practical engineering,when bolts with strength grade LC40 or above and diameter of 16 mm,19mm and 22 mm are used,the failure mode of stud connectors is shear failure of studs.(2)Compared with ordinary concrete stud connectors,the shear bearing capacity and shear stiffness of lightweight aggregate concrete stud connectors are lower and the peak slip is larger.(3)When the stud is damaged by shear,the main factors affecting the shear capacity of lightweight aggregate concrete stud connectors are: stud diameter,ultimate tensile strength and stirrups spacing.The shear capacity increases with the stud diameter and ultimate tensile strength increasing,while decreases with the stirrups spacing increasing.(4)For lightweight aggregate concrete stud connectors,the calculation formula of design value of shear capacity considering the effect of stirrup spacing is put forward.(5)For practical engineering,increasing the stud diameter is a more direct,effective and convenient way to improve the mechanical properties of lightweight aggregate concrete stud connectors.