Bolted shear connectors in steel–concrete composite structures: Shear behavior

Abstract

The use of bolted shear connectors is of great importance to the sustainable development of steel–concrete composite structures. In this paper, an experimental program consisting of four push-out specimens is performed to investigate the effects of bolt length and fabrication method of concrete slabs on the shear behavior of single-nut embedded bolted shear connectors in terms of failure mode and load-slip response. The concrete slabs are fabricated either as cast-in-situ monolithic slabs or precast slabs with reserved pockets which will be filled with grout in the final construction stage. The obtained results demonstrate that the fabrication method based on grouting, which is commonly utilized for strengthening and retrofitting works, does not affect the behavior of the bolted shear connection. Based on the experimental observations, a finite element (FE) model of the bolted shear connection is developed, after the obtained numerical results are verified against the test results obtained in this paper and those presented in other existing literature, a parametric study is carried out to further investigate the effects of the concrete strength, bolt strength, bolt diameter, bolt pretension load, and the length-to-diameter ratio of bolt on the performance of the bolted shear connection. Moreover, based on the obtained results, a design formula is proposed to obtain the ultimate shear resistance of the bolted shear connection, and the efficacy of the proposed design formula is proved through the comparison with the test results shown in the existing literature.