Proposal of new column support system for multi-story steel moment resisting structures to perform beam yielding mechanism

For the moment resisting frames with fixed column bases, the soft story mechanism may occur during earthquake due to become plastic hinges at the bottom part of columns. This paper proposes the new support system on the first story whose columns consist of the reinforced concrete downside column and the steel topside column, and their joints with the anchor bolts and the shear plates are supposed to be pinned. It is possible for the frames with this support system to uniform the magnitude of the bending moment at column top and base, and to perform beam yielding mechanism for 6 and 9 story frames with 2.1 of the column-to-beam full plastic moment ratio.