Experimental and nonlinear finite-element analysis study on lateral push resistance of San-dou components perpendicular and parallel to grain in traditional timber buildings

Abstract

Dou-gong is an essential part of traditional timber buildings in East Asia, having a decoration function and a load transfer function. The San-dou component, which is vulnerable to the lateral push force of the Gong, Fang, and purlin, is a critical structural component in the Dou-gong. In San-dou components, there are two distinctive types of surfaces subjected to lateral push force, perpendicular to the grain and parallel to the grain. However, few investigation into the structural performance of these two types has been done. Considering this shortcoming in the literature, in the current study, tests were carried out to obtain elasticity and strength characteristics on 90 timber specimens of fir and larch. After the material property test, 24 San-dou specimens were prepared to investigate the lateral push resistance. Consequently, an elastic–plastic damage assessment model was developed to calculate the load–displacement curve and possible damage distribution region of San-dou component, using the nonlinear finite-element analysis. According to the analyses, the failure mode for the San-dou component perpendicular to the grain is a horizontal crack parallel to the Dou-ear. Besides, the failure mode of the San-dou component parallel to the grain is an oblique crack, which begins from the inner edge of the Dou-ear to the lower part of the San-dou component. In the case of the other factors being the same, the bearing capacity of the larch San-dou component is 49.64–55.78% stronger than the fir San-dou component. Besides that, the bearing capacity of the San-dou component perpendicular to the grain is 32.85–38.22% higher than the San-dou component parallel to the grain. The research findings are expected to give a theoretical foundation for the structural evaluation of the Dou-gong system in traditional timber buildings and a scientific basis for elucidating the differences in the construction of traditional timber buildings in East Asia.