THE EFFECTIVENESS OF WIDE COLUMN LUMPING METHOD FOR PRELIMINARY DESIGN OF HIGH-RISE BUILDING

The rapid growths of the urban population and the consequent pressure on limited space have considerably made high-rise buildings used as feasible solution for housing and commercial needs. However, there are many complex and indeterminate problems, especially analysing high-rise building at the conceptual design stage. As pointed out in several researches, there are some available simplified assumptions to derive an equivalent structure which represent the essential behaviour of actual buildings. A careful analytical consideration should be taken from the initial design process. At present, lumping technique has been used to simplify a frame structural model by lumping a number of typical floors into a single floor. However, this method is available for frame structure . with column and beam members. It cannot be applied to structure with shear wall elements. Whereas, when the finite element analysis program is not available, wide column method can be considered for modelling shear wall of the structure. A more simplified assumptions, based on the two methods above, "Wide Column Lumping Method", is proposed in this study to find an equivalent structure to wall frame structure in high-rise buildings. Using this proposed method, the shear wall elements will be simplified as wide column and rigid beams and the size of structural model can be reduced by vertically combining a number of beams into single beam. A comparative study is developed to evaluate two 50-storey wall-frame structural models in two-dimensional analysis and three 50-storey symmetrical wall-frame structural models in three-dimensional analysis, using GT-Strudl structural analysis software package. A significant reduction in number of storeys in the equivalent structure, from 50 storeys to 14 storeys has been shown to be reasonably accurate. In terms of structural stiffness and member forces, this method gives a reasonable and realistic result. The correct conceptual and analytical treatment of high-rise building structural system at the initial design stages becomes very important as an initial step towards a successful design of high-rise buildings. Therefore, the proposed "Wide Column Lumping Method" would be useful to practising engineers and architects.

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• PO SENG KIAN