Flexible performance of traditional timber joints with various joint distances

Dieh-Dou type timber frame is one of the major types of the traditional timber frames in Taiwan. The column not only connects with multiple layers of beams along the in-plane direction but also connects with beams in the traverse direction at the same level. In this study, small joint distances and bi-axial bending effects on the flexible performance of the joints were investigated. A two-part series of fullscale, quasi-static cyclic tests were conducted. The first part involved the uniaxial testing of column connected with two different types of joint combinations, namely single layer of beam and double layers of beams with joint clearances of 6cm and 12cm. In the second part, the double-layer beam-column joint specimen with 6cm clearance was tested bi-axially. Each set of parameters has three identical specimens. Uniaxial tests revealed that the single-layer beam specimens could sustain a maximum strength of 7kN while the double-layer beam specimens with 12cm clearance reaches a strength of 16kN. Hence, the double-layer beam specimen is about two times stronger than the single-layer type. The maximum strengths of the double-layer beam with 6cm clearance are 11.5kN and 9.5kN when they sustain uni-axial and bi-axial bending, respectively. Column shear failures were observed in the specimens and should be one of the reasons responsible for the smaller maximum strength.