新しい柱脚機構を有する鉄骨ラーメン骨組の終局耐震能力及び鉄骨柱支点部の作用力の算定法

摘要

梁降伏型メカニズムを形成する鉄骨ラーメン構造物の保有水平耐力設計では，中程度の地震に対しては梁のみを降伏させ，大地震では柱脚部の降伏も許容されている。E-Defenseによる実大4層鉄骨ラーメン構造物の倒壊実験では，建築基準法に準拠した構造物に1995年兵庫県南部地震JR應取駅記録の100%の地震動を入力した際，最下層柱の脚部及び柱頭で局部座屈を生じ，最下層に損傷集中したため，構造物は倒壊した。%In the steel frames, the column base is allowed to yield after beam yielding subjected to large earthquake in Japanese design codes such as "The Building Standard Low of Japan" by Building Center of Japan. If the frames have unexpected seismic horizontal force, the soft story mechanism may occur. To prevent the plastic collapse of the column on　1st story, our previous paper suggested the new column support system on　1st story, which consist of the reinforced concrete downside column and the steel topside column. In this paper, the virtual work method is applied to estimate the damage distribution and the collapse deformation capacity of the steel moment resisting frames with these support systems, and the shear and axial demands the column joints on 1st story are clarified.