The Research On The Static Performance And Seismic Design Of Mega-frame Structures

With the development of the modern tall buildings, a new-structure named megaframe structure which belongs to super high-rise building structure system is emerged in recent twenty years. It is consisted of primary structure and secondary structure. It is considered one of the most economic structural systems for its excellent whole stability and great performance.The performance of mageframe structure was discussed as follows.(1) The mageframe structure coule be divided into continuous and uncontinuous hypo-frame column according to the hypo-frame column closed to the main frame beam, which there were the two different models. The former can be caculated by the modified D value method considering the rigidness and shear deformation of main frame column and beam. It is handy and accurate enough to calculate the mageframe structure with the continuous hypo-frame column. However the D value method could not to calculate the mageframe structure with the uncontinuous hypo-frame column, so the new method to calculate the anti-side rigidness of frame was put forward, and its applicability was wider, which can calculate the mageframe structure with the uncontinuous hypo-frame column.(2) With the increase of mageframe structures, the beam-column reasonable arrangement becomes the key problem. At the condition of equal total section area of beam-column, changing the size and number of the main beam-column and the minor beam-column separately, the different structural free vibration periods, structural side placements and structural moments were compared, the influence of the main and minor frame beam-column arrangement on behaviors of mageframe structures were discussed, and some reasonable suggests were put forward in engineering practice.(3) The ratio of scantlings between the main beam-column and the minor beam-column should be appropriate. It would not be an optimization program if the ratio is too large, as soon as too small. At the condition of equal total section area of beam-column, changing the scantlings ratio between the main beam-column and the minor beam-column, and between the main beam and the main column. The influences of these factors on static and dynamic performance of mageframe structures were discussed.(4) The researches and exploring of the seismic capacity and the dynamic performance of the mageframe structures, the overall stability, the ability of anti-collapse in the earthquake, the emergence and distribution of the plastic hinge, the internal force and deformation of the structure in the rare occurrence earthquake were essential for the wide applications of the megaframe structures and the settings of the specification about megaframe in our country. By the analysis of a design example and the pushover analysis of a simulation case, the seismic capacity and the dynamic performance, the ability of anti-collapse and the security of the mageframe were discussed. At the same time, some summary and advices based on this paper about designs and construction in megaframe was given, by the seismic design principles and methods of the high-rise building structure (especially the frame structure) and the related research results.