Quantitative contribution assessment of joints and components to the load-carrying capacity of ancient timber frame

Abstract

This paper aims to quantitatively assess the contribution of the joints and components to the load-carrying capacity of the ancient timber frame. Firstly, the explicit expression of the restoring moment and rotational stiffness of the column foot (CF) with circular cross-section is derived. Also, the restoring moment of the dovetail mortise-tenon (DMT) joint is introduced and its rotational stiffness is derived. Then the DMT joints connected timber frame model is established by the beam and spring elements, and its accuracy is checked by the corresponding model by solid elements in Abaqus. Finally, the contributions of the columns, beam and DMT joints to the load-carrying capacity of the timber frame under different vertical loads are quantitatively assessed. The results show that the horizontal force of the timber frame basically increases with the loading displacement when the vertical load at the column head is small; that increases to the peak value and then decreases with the loading displacement when the vertical load at the column head is relatively large. Although the timber columns provide up to about 80% of the load-carrying capacity of the frame during the whole loading process, the DMT joints provide more than 65% of the final load-carrying capacity, and the contribution promotion of the beam to the load-carrying capacity of the timber frame maintains 5%.