STUDY ON SHEAR PERFORMANCE OF GROUP STUD CONNECTOR UNDER THE QUASI-STATIC LOAD

To study the deterioration process and degradation mechanism of stud connectors under low-cycle reciprocating load, nine specimens were designed with the stud diameter, concrete strength and loading scheme as the parameters. The specimens were subjected to quasi-static low-cycle reciprocating load. Based on the experimental results, the model performance was simulated by the finite element software ABAQUS. The failure mode, stiffness degradation, damage accumulation and energy dissipation performance of stud shear connectors were analyzed. The results show that when the concrete strength is the same, the shear strength of the specimen increases with the increase of the diameter of the bolts. The effect on the shear stiffness and energy dissipation performance is not obvious. With studs of a large diameter, the performance index of the specimen will decline. The increase in concrete strength can improve the shear strength, shear stiffness and energy dissipation of the specimen, but the displacement of the specimens is decreased. When a reciprocating cycle is loaded at a low stress, early damage accumulation occurs in the test. The speed of injury accumulation increases with the increase of the diameter of the bolts. When a high stress cycle is loaded, the test shows an accumulation lag of damage, and rapid damage accumulation begins in the third cycle section. When the group studs are arranged in multiple layers, the shear force of the studs near the loading end is greater than that of the other studs as a result of the uneven transfer among the studs. When the concrete strength is between C35 and C45, it is recommended to use studs of a diameter of 16 mm to match it.