Estimation of splitting strength of bolted timber joints loaded parallel to wood grain, 1: Effect of end distance, loading rate, and fundamental specimen properties on splitting strength
2004
Aoki, K. (Tokyo Univ. (Japan)) | Tsuchimoto, T.
The ultimate fracture mode of bolted timber joints is splitting. Since the prediction of splitting strength is too difficult, bolted timber joints are designed by considering sufficient end distances, safety factors, and so on. In this work, bolted timber joints were subjected to double shear tests in order to study priority factors that determine the splitting, strength of bolted timber joints loaded parallel to wood grain. Fundamental physical properties, such as specific gravity, moisture content, modulus of elasticity, annual ring width, and annual ring angle, were measured in advance. A monotonic loading test was conducted on specimens, varying end distances and loading rates. The bolt diameter was 16 mm. A multiple regression analysis was performed and the priority factors that decide the splitting strength were evaluated. The results of the double shear tests and the multiple regression analysis are summarized as follows : End distance and maximum load or referenced strength had a significant correlation when the end distance was not more than 6d (d=bolt diameter). If the end distance became more than 6d, maximum loads were nearly constant. The most important factor to determine the maximum load was the end distance. The standardized partial regression coefficient of specific gravity was half that of the end distance. While the loading rate and the annual ring angle slightly affected the maximum load or the fracture mode; their priority was low.
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