Testing and Evaluation of Metal-Plate-Connected Wood Truss Joints

Abstract

Abstract Five different types of metal-plate-connected (MPC) wood joints from a scissors truss were tested to evaluate their behavior. All joints were tested in a unique testing apparatus where in-plane loads along with moments were applied to simulate loads carried by the truss members. Strength, stiffness, and failure modes for bottom chord splice joints at web (BSJ), heel joints (HJ), crown joints (CJ), bottom chord ridge joints (BRJ), and top chord splice joints at web (TSJ) were reported. The average strengths of the BSJ, HJ, CJ, BRJ, and TSJ were 51 200 N, 49 800 N, 33 000 N, 52 300 N, and 43 100 N, respectively. The average values of the rotational stiffness were 245 440 kNmm/rad, 249 600 kNmm/rad, 103 700 kNmm/rad, and 33 800 kNmm/rad for BSJ, HJ, BRJ, and TSJ, respectively. Average transitional stiffness values were 61.7 kN/mm for BSJ, 29.2 kN/mm for HJ, and 40.2 kN/mm for BRJ. The majority of bottom chord joints failed in plate tearing, whereas top chord joints generally failed in a web member withdrawal mode. The joint stiffness data were used in a preliminary finite element (FE) analysis of the same truss, and the analytical results compared well to actual full-scale truss test results. Stiffness and strength data will be used in a future FE study.