Experimental study and simulation analysis on the connection performance of a new tubular glulam bolted joint

Abstract

Modern timber structures represented by glulam structures have recently been widely developed. The joint connection performance is essential for the overall structural strength, especially in high-rise or large-span timber structures. In this paper, three-point bending tests were carried out on Buckling-Type (BT) and Reinforced-Type (RT) joints to investigate the damage modes and the effect of different axial forces on the connection performance. A finite element model (FEM) of the BT joint (belonging to the single-direction (SD) joint) was established based on ABAQUS and verified with the experimental results. The SD joint FEM was extended to the three-direction (TD) joint FEM, and the connection performance of the TD joint was analyzed under the action of combined axial forces in different directions. Experiments and finite element analyses showed that the BT joints were damaged by buckling of the upper part of the steel tube, and the RT joints were damaged by transverse cracking of glulam. The axial tension force can increase the ultimate bearing capacity, while the axial compression force has the opposite effect. Increasing the absolute value of the axial force can improve the initial rotational stiffness of the bolted group connection. The three directional flanges constrained to each other could provide additional strength and stiffness in the TD joint. When the relative values of axial compression and tension forces are constant, the combination of different directions of axial forces has little effect on the TD joint’s ultimate bearing capacity.