Experimental study on bearing capacity of steel-pipe PBL shear connectors

In composite open-web sandwich plate structures, when the span is large, the restraining effect of the bottom chords on the top chords makes the stress state of the material interfaces tend to be complicated, which restricts the structural load-bearing capacity. Therefore, To improve the overall stress state of such structures and increase their load-bearing capacity, this study introduces an innovative design for Steel-pipe PBL shear connectors (Perfobond rib shear connectors). In this design, steel pipes are welded to the openings of conventional PBL shear connectors. By utilizing the circular cross-section of the steel pipe to resist the complex stresses at the material interfaces, the stiffness of the shear connectors and the load-bearing capacity of the structure are improved at the same time. This study evaluates the shear performance of the new PBL shear connectors by testing nine specimens with varying parameters: steel pipe diameter, length, wall thickness, perforated rebar diameter, and concrete strength. The results indicate that steel pipes modify the failure mode and bearing mechanism of conventional PBL shear connectors, significantly enhancing shear stiffness and ultimate bearing capacity. Among all parameters, the steel pipe diameter has the most substantial impact on the bearing capacity of Steel-pipe PBL shear connectors. Based on the experimental data, this article presents a calculation formula for assessing the ultimate bearing capacity of Steel-pipe PBL shear connectors.