Shear performance of welded stud connections in steel-cross laminated bamboo and timber composite structures

Cross laminated bamboo and timber (CLBT), as a low-carbon and environmentally friendly material, offer a viable alternative to traditional concrete. A novel steel-CLBT composite connection was proposed to explore the potential of CLBT in construction. A total of 24 push-out specimens were designed in this study, featuring a grout connection that utilizes magnesium phosphate cement (MPC) mortar as the grouting material. Eighteen specimens were equipped with stud connectors, while six featured bolt connectors. Four variables were investigated: stud diameter, CLBT slab thickness, fiber orientation of the CLBT slab, and the type of connection. The failure modes of the connections and the strains of the connectors were analyzed, alongside an evaluation of the mechanical properties, including shear capacity, stiffness, ductility, and load-displacement curves. The test results demonstrate that the use of large-diameter stud connectors significantly enhances the mechanical performance of the connections. While the three different connection types have minimal impact on shear capacity, they do influence stiffness. Finally, an accurate theoretical formula for calculating shear capacity was proposed, along with a load-displacement model, offering valuable theoretical support for future applications. © 2025 Institution of Structural Engineers