Research On The Displacement-based Seismic Design Method Of Steel Moment-resisting Frame (SMRF)

The displacement-based seismic design method is a prevailing research topic in the 21^st century, whose philosophy is to ensure the function of buildings to meet the requirements of users and society in different intensity of earthquakes. However, the traditional philosophy of seismic design is only to ensure life safety, but cannot fulfill the multi-performance objective of buildings. Accordingly, the research on displacement-based seismic design method of steel moment-resisting frame is of great theoretical significance and engineering application value. The main contents of this dissertation are as follows:(1) The displacement-based seismic design methods and their application in home and abroad have been summarized. Then the representative methodologies of Pushover method, capacity spectrum method, displacement modification procedure and N2 method are introduced. The uses of Pushover method and capacity spectrum method have been emphasized as well as the present problems of both methods. Meanwhile, the seismic design methods of steel moment-resisting frames are also recommended.(2) Three displacement-based seismic design methods of steel moment-resisting frame have been investigated, that is, based-ductility method, direct displacement-based design method and capacity spectrum method; the comparison is made between them. Then, researches have been done on such problems as the determination of performances objective and equivalent linearization system etc. The modified method of plastic hinge to deal with all kinds of nonlinear problems has also been investigated, and the existing problems in this method are analyzed, combined with the present research status.(3) The direct displacement-based seismic design method of steel moment-resisting frame has been put forward herein. The dependency equation of maximum displacement profile and maximum interstory drift ratio is established for steel moment-resisting frame. The procedures of direct displacement-based seismic design of steel moment-resisting frame has also been addressed including the establishment of steel moment-resisting frame displacement profile and equivalent single-degree-of-freedom system and the determination of target displacement. In accordance with the maximum displacement profile of steel moment-resisting frame proposed in this paper, a case study on five-storey steel moment-resisting frame is demonstrated.(4) The capacity spectrum of seismic design method of steel moment-resisting frame has been discussed and the procedure of its application has also been addressed including the establishment of capacity spectrum curve and demand spectrum curve, the determination in performance point, the evaluation of seismic performance on structures etc. According to the capacity spectrum method, another case study for five-storey steel moment-resisting frame is verified.The research results indicate that the displacement-based seismic design method steel moment-resisting frame is of simplicity, utility and convenient operation; this method can not only realize structural designs in different levels of performances, but can permit control over the performances of structures under earthquakes of varied intensities.