梁ウェブにおけるモーメント伝達効率が低い柱梁接合部の繰り返し載荷実験

摘要

柱を角形鋼管とした柱梁接合部では、梁ウェブから柱へのモーメント伝達は柱のスキンプレートを介して行われるが、スキンプレートが面外に変形することから、特に柱板厚が薄い場合にはスキンプレートの面外剛性および耐力が不足し梁ウェブにおけるモーメント伝達効率が低下する。日本建築学会鋼構造接合部設計指針(以降、接合部設計指針)には、極限解析に基づく梁ウェブのモーメント伝達効率を考慮した接合部の最大耐力の算定法が示されており、柱と梁の断面および鋼種の組み合わせ、スカラップの有無を考慮して、接合部の最大耐力を評価することができる。%When SN490 beam is connected to BCR295 column, especially when the joint efficiency at beam web is low, there is a high possibility that the connection does not meet the joint coefficient criteria of connection strength. A comprehensive evaluation of the plastic deformation capacity of these connections is necessary. Nineteen beam-to-column specimens with joint coefficients ranged from 0.97 to 1.39 were tested under incremental cyclic loadings. The plastic deformation capacity, maximum strength, yield strength and full plastic strength of the specimens with different failure modes were evaluated quantitatively. The test results show that for the specimens with low joint coefficients, although the plastic deformation capacities are not particularly good, these specimens reached the minimum requirements of seismic design. The test results also indicate that the "Recommendation for Design of Connections in Steel Structures" provides accurate evaluation of both the maximum strength of beam-to-column connections and joint efficiency on the safe side.