Experimental study on the shear behavior of a bolt connector in a steel-concrete composite beam

The diameter of a traditional bolt connector is smaller than that of the predrilled holes in a steel beam, resulting in a gap between the bolt and the hole wall, possibly causing a relative slip between the steel beam and the concrete slab on the top, thereby increasing the deflection of the combined beams. To minimize or eliminate the above mentioned gaps, the reamer and threaded hole bolts are introduced as the shear connectors of composite structures, and the cone sleeve self-lock bolt connectors are proposed. Eight push-out tests were designed and implemented on the bolt connectors. According to the load-slip curve of each specimen, the specific differences in shear mechanical properties, such as shear-bearing capacity, slip capacity, and shear stiffness between three types of bolt connectors and traditional bolt connectors, were studied, showing that the failure modes of the three bolt connector types are consistent with those of the traditional bolt connectors. These failure modes are the shear failure of the bolt rod, and the concrete around the bolt has no peeling phenomenon. All three bolt connectors are similar to traditional bolt connectors in terms of shear-bearing capacity. According to the load-slip curve of the specimen, these three bolt connectors can be divided into elastic, elastic-plastic, and failure stages. The ductility coefficient and shear stiffness of the three bolt connectors are better than those of the traditional bolts. Considering the mechanical properties, construction performance, and economy, reamed bolt connectors should be used as the shear connectors of composite structures. © 2024 Editorial Board of Journal of Harbin Engineering. All rights reserved.