In this thesis,Torsion effect irregularity on the behavior evaluation of the concrete structures with concrete shear wall.One of the important concepts in analysis and design of structures is irregularity.in the previous earth quakes many of buildings were disturbed because of irregularity. irregularity changes the behavior of structures and causes stress concentration. the international seismic codes classify irregularities into two parts : irregularity in plan and irregularity in altitude.
Iranian seismic code (Standard 2800) has classified irregular buildings in plan into five: irregularity numeral, torsion, to diaphragm, sheet in out , system un exampled. In this thesis, in this regard 3 concrete buildings with seven stories each , with the combined system of moment resistant frame and the shear wall in symmetric and non symmetric conditions are evaluated. These structures initially , have been analyzed and designed with respect to standard Iranian earth quake code (2800) and Iranian concrete code (ABA).The respective displacement of each story is derived. These results are compared with accepted criteria and the performance level of the structure in defined.It is concluded that for the evaluated buildings in this research, by the increase of the irregularity, the performance of the buildings goes from immediate occupancy to life safety ,in fact, by the increase of the irregularity of the buildings ,the performance will remain in acceptable range, which is life safety, based on standard code 2800.