Performance evaluation of innovative triangular and spherical ribbed headed studs in composite steel beam-concrete slab junction

Abstract

Composite structures have now become a popular practice in the construction of bridges and RCC structures. Various advancement has been taken in several decades to ensure the composite action between the concrete and steel interface. Shear connectors were developed to ensure this composite action in between the steel and concrete interface of the composite junction. The two types of connections that are most frequently used in composite construction are headed stud shear connectors and channel connectors. The maximum stress concentration of the headed stud shear connector occurs on the bottom of the headed stud shear connector. As a result of the higher stresses at the bottom of the headed stud shear connector the bending height of the headed stud shear connector varies in between 18 to 33% depending upon the grade of concrete. The present study intends to study the effect of geometric variation in headed stud shear connectors according to the requirement of the cross-section. The geometric variations were made with reference to bending height throughout the shank of headed studs. Based on the stress variation the headed stud shear connector is divided into three different zones. For making these variations the headed stud was distributed into three zones. Zone 1 is the headed region of the connector. Zone 3 is the bottom region with maximum shear concentration and zone 2 is the part of shank connecting the zone 3 and zone 1 of the headed stud shear connector. In present study volume reduction is done in the zone 2 region of the headed stud shear connector and volumetric addition is done in the zone 3 region of the headed stud shear connector. Based on the proposed ideology for creating geometric variations, two different studs are proposed namely spherical ribbed headed studs (SRHS) and triangular ribbed headed studs (TRHS) studs. Performance of the proposed SRHS and TRHS shear connectors was evaluated using six experimental specimen and Finite element analysis. Results show that SRHS and TRHS studs have higher shear carrying capacity, ductility and stiffness compared to conventional headed stud shear connectors.