Assessment of the Torsion Effect in Asymmetric Buildings Under Seismic Load

Irregular structures are more and more used in new architectural design. In these structures the torsion phenomenon can induce important stresses especially in the case of a seismic motion. The new seismic codes try to take into account this effect and during the modeling it is difficult to assess all the parameters that have an influence on the behavior of this kind of structures. In this work, a study on the influence of the torsion effects on the behavior of structures is done. Two types of buildings are considered, one symmetrical and the other asymmetrical in terms of rigidity. The proposed structures consist of a building in reinforced concrete with infinitely rigid slabs and frames. The use of a finite element code which takes into account the nonlinear behavior of structural elements allows temporal analysis. A database of 116 seismic records is used. These signals represent earthquakes with magnitude ranging between 6.2 and 7.7. The responses of the two buildings are compared in terms of maximum displacement at the top, ductility and reduction factor.