Shear performance of embedded rebar shear connector in composite beam with perforated rectangular steel tube: Testing and analysis

The composite beam with perforated rectangular steel tube (PRST) is a type of U-shaped steel-concrete composite beam composed of perforated rectangular steel tubes, concrete flange, and in-filled concrete connected with shear connectors. The manufacturing industrialization and the construction efficiency of this composite beam are high. However, traditional shear connectors are unsuitable for this beam due to problems like welding quality. Therefore, an embedded rebar shear connector (ERSC) is proposed in this paper to solve the above problems. To investigate the shear performance of ERSC, push-out tests are conducted. The test results show that the failure mode of ERSC specimens mainly characterized by concrete cracking, slip at the steel beam-concrete flange interface and crushing at the bottom of the specimens. The shear performance of ERSC specimens is significantly influenced by the quantity, strength and diameter of ERSCs, while the influence of spacing is relatively small. After verifying the accuracy of the model by finite element analysis, parametric analysis was carried out, and the results show that the shear performance of ERSC specimens increases significantly with the increase of strength of concrete, strength of ERSC, diameter of ERSC and hole width of PRST, which is similar with test results. Based on test and finite element analysis results, the shear capacity of the ERSC specimens is provided by the shear effect of ERSC, the shear effect of steel-concrete bond, and the shear effect of concrete tenon at holes. A high-precision calculation formula for the shear capacity which is derived by existing formulas with test and finite element data is proposed in this paper. This study provides a solid foundation for the design and application of ERSC.