超高層鋼構造建物の現場溶接接合部が有する耐震性能を検証するE-ディフェンス震動台実験

摘要

実大の鋼架構を2体建設し，それぞれの架構に21階建ての建物と同じせん断振動特性を付与し，E-ディフェンス震動台で加振した。この振動台実験から以下の知見を得た。1)超高層鋼構造建物は長周期地震動によって降伏限内外の小振幅変形を極めて多く経験し，最大層間変形が0.02ラジアンに至らなくても，1970年代の設計詳細と現場溶接技術で施工された柱梁接合部は損傷する危険性がある。損傷は，梁下フランジを柱に接合する完全溶込み溶接の近傍に集中する。%Two full-scale steel moment-resisting frames were constructed and tested at E-Defense to examine the performance of high-rise buildings subjected to long-period ground motions. Frame 1 adopted typical design and detailing from the 1970's employing both field-welded and shop-welded details for the moment frame connections. Frame 2 was identical to Frame 1 except that all connections were field-welded and upgraded using three strengthening methods. A number of connections in Frame 1 fractured during a simulated long-period motion. No damage was observed in Frame 2 until the same motion was repeated multiple times. The performance of field-welded connections in existing high-rise buildings and the effectiveness of upgrade methods are discussed.