A new algorithm for geometrical design of asymmetric tall buildings against seismic torsional behaviour

This paper presents a new algorithm developed to minimize the torsional effects in asymmetric tall buildings, through arriving at all possible orientations of rectangular columns that have different lateral stiffnesses and strength in two principal directions. The most suitable combination of different orientations of such columns are chosen for the design, which leads to minimum torsional effect. The developed algorithm is coded in MATLAB and the eccentricity of a given asymmetric tall building is minimized through the proposed algorithm. Three‐dimensional model of the building is constructed and its modal analysis is performed to obtain mode shapes using SAP2000 finite element program. Finite element model of the building is updated to eliminate the torsional moments by applying developed algorithm. Earthquake behaviour of the building is investigated using 1999 Kocaeli earthquake before and after this geometrical design. It is seen from the analysis results that the torsional moments are almost eliminated and the maximum principal stresses on shell elements are extremely reduced after system design depending on the proposed algorithm. In addition to this, it is realized that structural modal behaviour of the building is changed from torsional to translational. Copyright © 2010 John Wiley & Sons, Ltd.