Abstract
Designing space frame, buckling is the most important phenomenon. The purpose of this study is to estimate the buckling strangth of round thimbers (Japanese cedar and Japanese cypress) and to evaluate the influence of several characters such as knots and average width of annual rings and so forth. By full-size test, two factors: initial deflection and average width of annual rings were found to be the major points. By regulating these two factors, specified design strength of buckling is defined based on the standard strength by Architectural Institute of Japan code.
