Glued build-up members (GBM) are structural building members that are developed as an application to effectively utilize box-heart timbers. The purpose of this study is to establish a method for evaluating the bending performance of a GBM. In this paper, we analyze the effect of stress distribution and dimensions (Size effect) on the bending strength of GBM. As a result, in the evaluation of the bending strength of GBM, the tensile strength and bending strength of the bottom timber are reduced according to the dimensions, and the combined stress method is appropriate.
