in order to investigate the effects of torsion on moment and shear values of vertical structural elements, a typical model building has been selected. Torsional irregularity has been created in the building by changing the location of the shear walls. Three cases of different centers of rigidity for 1, 5, and 10-story buildings have been considered. Each case has been analyzed by both the methods of equivalent earthquake loading and dynamic analysis, and the results compared. In order to investigate the effects of nonorthogonality on the distribution of moments and shears of the vertical structural elements, a 5-story building has been studied with one nonorthogonal and two orthogonal shear walls. Three cases of different orientations of the nonorthogonal wall have been considered. Each case has been analyzed for five different directions of earthquake. (C) 2001 Elsevier Science Ltd. All rights reserved.