Strength Estimation and Reinforcement of Glue-Laminated Timber Beams with Circular Through-Hole

摘要

The purpose of this study is to establish a simple and effective way to reinforce glue-laminated timber beams with a circular through-hole having a diameter that is at least 1/3 the beam height. Experiments with bend and shear tests and finite element analyses were used to determine the stress fields and fracture conditions around the hole and estimate the maximum strength of the beams. Beams with the hole were found to have 60 to 80% of the yield strength of beams without the hole. In the experiments, it was observed that fractures occurred at the point where the tensile stress exceeds the tensile strength of the beam. This indicates that reduction of the tensile stress around the hole is needed. Based on these results, we propose two reinforcement methods, one using wooden boards and the other using toothed steel plates, for timber beams with a hole. The effectiveness of the proposed methods is shown by the experimental results.