火災加熱が木材の力学的性能に及ぼす影響: 加熱した針葉樹材及び広葉樹材の高温時及び加熱冷却後のヤング係数•曲げ強度の測定

摘要

近年、木造建築は森林资源の管理や低炭素化等、様々な方面から注目されており、大規模建築への木造活用に向けた法整備や行政的施策が進められている。今後、大規模建築に適した耐火·準耐火構造等の木造部材の開発が期待されるが、効率的に技術開発するには、火災加熱による部材の力学的性能の変化を予測できるようにする必要がある。%Young's modulus and bending strength of 3 species of wood commonly used for engineered wood and Zelkova, hardwood normally used for traditional large building, heated up to 250℃ are measured at the elevated temperature and after cooling to the room temperature as an engineering basis for the structural fire safety design and the reusabitity diagnosis of large-scale timber buildings. The results show the both properties, either at elevated temperature or after cooling, are highly dependent on exposed temperature for 150-200℃ or higher, and correlation between the Young's modulus and the bending strength tends to become weaker with rise of exposed temperature. The bending strength at elevated temperature is found to converge while it is notably scattered at normal temperature.