Displacement-based Seismic Design For Concrete-filled Steel Tubular Frame

For the past few years, concrete-filled steel tubular structures are used more and more extensively in the building industry. The performance/displacement-based seismic design method for concrete-filled steel tubular frame is studied in this paper. The determining method of displacement target for concrete-filled steel tubular frame is proposed. The resolving train of thought and tactics are advised for the some referred problems in the design.The main achievements can be summarized as follows:(1) The lateral displacement mode, story drift angle mode and story shearing force mode of concrete-filled steel tubular frame structure are studied by two examples of concrete-filled circular/square steel tubular frame with static force nonlinearity analysis.(2) Displacement target of concrete-filled steel tubular frame is determined by the story drift angle and lateral displacement mode. The story drift angle of frame is determined by performance level. The displacement objects are obtained by the lateral displacement mode.(3) Relations between the storey drift of frame and deformation of members are studied. The story drift can be represented by the drift of a typical beam/column sub-assemblage. Transformation rule of frame is obtained by the standard of force balance and displacement balance.(4) The basic method and step of displacement-based seismic design for concrete-filled steel tubular frame is investigated, and the design practice is carried out with typical example. The result is verified with the capacity spectrum method.In a short, the displacement-based seismic design can make concrete-filled steel tubular frame have sufficient displacement capacity to meet the displacement demands, and achieve the prospective performance objects.