Mohammad Ghasem VETR - Professor Assistant, International Institute of Earthquake Engineering and Seismology, Tehran, Iran
Bahram KORDBAGH - Master of Science Student, International Institute of Earthquake Engineering and Seismology, Tehran, Iran
Kiyanoush GHAZVINI - Master of Science Student, International Institute of Earthquake Engineering and Seismology, Tehran, Iran

According to the fundamental role of lateral resistance elements in tall structures, to cope with the earthquake forces and sort the elements constrains, present research as for the asymmetric posture braces is performed in the steel structures. In this study, after reviewing the effect of eccentricity of center of stiffness towards the center of mass and torsion caused by it in a building that has been implemented in the past. Also by changing the arrangement of braces, the amount of steel consumption is an important economic indicator in each of the Items is analysed. Then the displacement parameter is the criterion used for the detection of structural damage was evaluated. Finally, the base shear changes, is examined according to eccentricity. Due to the size and geometry of the ground reality is such that Makes have an irregular structure in plan that placed under torsion. In this study, we examine a building that has been implemented in the past, and we show that near the center of mass and stiffness, and reduce the eccentricity of the appropriate layout braces, how much base shear and structure weight (steel consumption) is reduced. And also we start type of analysis to the sensitivity of the irregular structure under torsion. In this study, two types of analysis included quasi-static and dynamic spectral analysis is studied

Seismic Design, Irregular Structure, Brace, Steel Buildings