Fire Resistance and Failure Mechanism of steel-to-timber dowelled connections at the end of glulam beams

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H02281
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 23010:Building structures and materials-related
• Research Institution: Chiba University
• Principal Investigator: Hirashima Takeo 千葉大学, 大学院工学研究院, 教授 (20334170)
• Co-Investigator(Kenkyū-buntansha): 戸塚 真里奈 千葉大学, 大学院工学研究院, 助教 (60893774)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 木質構造 / 接合部 / 耐火性能 / 火災 / 耐力 / 回転剛性 / 破壊性状 / 伝熱解析

Outline of Final Research Achievements

In this study, load-bearing fire tests of timber frames using structural glued laminated timbers to clarify the structural fire behaviors and fire resistance of the timber connection.
Then, the followings are clarified: (1) the influence of tree species, beam cross-sectional dimensions, and connections on the failure time of the timber frame exposed to fire heating, (2) shear strength and failure behavior of the connections in fire, and (3) embedding strength and stiffness of the dowelled connections at high temperature.
Furthermore, the followings are suggested: (4) a non-linear rotational spring model of the timber connections, (5) a three-dimensional heat transfer analysis method considering a heat bridge at the joint metal, and (6) fire-resistance reinforcement methods of the timber connections.

Free Research Field

建築構造、耐火構造

Academic Significance and Societal Importance of the Research Achievements

本研究では、木質構造が本来有する火災時耐力に立脚した耐火設計方法を構築するため、その構築に不可欠である柱梁接合部の火災時挙動および耐力に関する知見を蓄積した。また木質構造の火災時挙動の予測に不可欠な接合部の伝熱解析手法および力学的挙動モデルを提案した。それらは、国産材のスギとカラマツを用いて検討された。
以上の知見および提案が大規模建築物の耐火性能を把握するための一助となり、国産材の有効利用につながることが期待される。