Prediction of the buckling stress of intermediate wooden columns using the secant modulus

Abstract

We made several buckling tests of wooden columns with intermediate slenderness ratios (λ) and examined the empirical formulas. On the basis of the examination, we formulated an equation for predicting the buckling stress (σ) of an intermediate wooden column. Sitka spruce (Picea sitchensis Carr.) and buna (Japanese beech, Fagus crenata BI.) were used for the studies. A compressive load was applied on the specimen supported with pin ends, and the buckling stress was predicted by the tangent modulus theory and two empirical equations: those of Tetmajer and Newlin-Gahagan. The predicted σ-λ relations were compared with the test results, and the applicability of these predictions were examined. Based on the comparisons, we formulated an equation that can predict the σ-λ relations of materials with various stress-strain characters in the plastic strain range.