Modified traditional Japanese timber joint system with retrofitting abilities: Fid-Bau Portal

Modified traditional Japanese timber joint system with retrofitting abilities

Shiratori, Takeshi / Komatsu, Kohei / Leijten, Adrian

10.1002/stc.240.abs

Embedment is a key feature of timber joints envisioned as the ultimate solution in avoiding the devastating full collapse of timber structures in seismic countries. The Japanese traditional timber post‐and‐beam structural system utilizes moment‐resisting joints based on embedment. Despite the joint's advantages having the ductile and energy‐absorptive behavior continuously to the post‐elastic phases, a primary shortcoming needs to be resolved—specifically of having the low and unreliable initial stiffness due to the gap formation between the contacting members. Further, large‐dimensioned timber most suitable for the embedment‐type joint is scarce and the lower quality of available timbers is making the modern applications difficult. A new timber joint capable of sustaining future seismic impacts is being pursued using various approaches. As a result of the optimization to satisfy the manifold studies, two traditional elements, namely Kusabi wedge and side‐penetrating Nageshi beam, are combined and tightened by the penetrating steel bolt. Its tightening system eliminates the gap formation in the joint, and heightens its performance over the traditional embedment‐type joints. Additional features, such as the damage‐inducing and fast seismic‐retrofitting ability, are also integrated. This new proposal for the ‘Kusabi–Nageshi’ (K–N) timber joint system aims to provide a new alternative to the joints used in seismic countries. Copyright © 2008 John Wiley & Sons, Ltd.