Research on mechanical property of glued timber truss connected by steel plates and bolts

Abstract

In order to deeply understand the mechanical performance of glued-laminated timber trusses connected by steel-plates and bolts, two groups of truss specimens were designed and fabricated by changing the connection forms of the nodes, while maintaining the height and span of the trusses unchanged. Each group of truss specimens was subjected to the mid-span load. At the same time, finite element numerical analysis was conducted on the tested trusses. Based on the agreement between the experimental and numerical simulation results, the influence of the parameters of thickness-to-diameter ratio and height-to-span ratio on the mechanical performance of these trusses was explored. The research results show that both types of node connections in the glued-laminated timber trusses have good bearing capacity. The main failure modes are the splitting of the diagonal web members at the mid-span node and the crushing failure of the bolt holes. The HJ-C type truss, which has the upper and lower chord members connected, exhibits better ductility, greater stiffness, and better structural synergy in load-bearing capacity. As the thickness-to-diameter ratio increases, the form of the bolts at the truss failure gradually changes from being straight to yielding. The optimal thickness-to-diameter ratio is 8.3. As the height-to-span ratio decreases, the initial stiffness and ultimate load-bearing capacity of the truss show a decreasing trend. The truss exhibits better mechanical performance when the height-to-span ratio is 1/4.