Engineering structures in the vicinity of causative earthquake faults have experienced severe damage during strong earthquakes of the past decade. Earthquake ground motions, recorded in near-fault zones differ from those observed in the far-fault regions. Near-fault ground motions often possess distinct characteristics, which can have strong influence on structural response. These include the rupture directivity effect in the fault-normal direction and the fling step in the fault-parallel direction. A site in the nearfield region of the fault may experience forward directivity when the fault rupture propagates towards the site with a velocity almost equal to the shear-wave velocity of the ground medium. The resulting ground motion typically exhibits a two-sided, long-period, large-amplitude velocity pulse in the fault-normal direction. Backward directivity occurs when the fault rupture propagates away from the site. The resulting ground motion tends to be of low intensity and long duration. In this thesis buildings asymmetric torsional behavior of RC moment frames and shear wall dual system is studied. Observations made after severe earthquakes has shown that asymmetric structures may experience severe injuries. state of asymmetric Considered, is asymmetrical in plan with eccentricity of stiffness. In this research, trying is to properties of studied systems Greatly be close to the actual structures. Accordingly, the studied structures is Consist of 7, 12 and 18 story, as well as for creation of eccentricity of stiffness in the structure, Is considered to be one of common eccentricity in the real structure and various values of eccentricity used for created of asymmetry.