EFFECT OF MULTI-LAYER LEANING COLUMN ON DAMAGE CONCENTRATION MITIGATION OF MULTI-STORY STEEL MOMENT RESISTING FRAMES WITH MID-STORY PIN COLUMN BASE SYSTEM

According to current design practices of steel moment-resisting frames, formation plastic hinges is unavoidable when the frames are supported by conventional column base systems, i.e., exposed-type and embedded-type due unequalized flexural moment demand on top first story columns [1]. Kimura et.al [3] has proposed mid-story pin system avoid from yielding realize beam-yielding mechanism applying connection between upper bottom RC at midpoints story. Previous analytical study [3~7] indicated that with exhibits superior seismic behavior than those mitigating probability yielding. However, it also revealed difficulty beam for commonly adopted column-beam strength ratio 1.4-1.8. Dual structural main frame resisting lateral force backed up secondary system. studies [8~15] shows such as a force-demand spreading [12] rocking wall [14], sufficiently contribute redistribution inelastic over height frames.