Seismic design approach for multi-story frames on the top story of which damage concentrates

Energy absorption capacity is an indispensable property for earthquake resistant structures. To equip a top story with abundant energy absorption capacity and to make energy inputs done by earthquakes concentrate on the top story results in an promising design option which has not been hitherto fully investigated. In this paper, the mechanism through which the energy input moves to the top story is clarified and the design criteria for this type of structures are demonstrated to be expressed in terms of D-s-values. This type of structures can be also applied to strengthen the existing structures which are judged to be insufficient in energy absorption capacity. By adding the damage concentrating story at the top of existing structure, the seismic performance of the structure can be highly improved without disturbing its living function.