Seismic Behavior of Asymmetric Two-Story X-braced Frames

Abstract

Concentrically braced frames (CBFs) are one of the efficient lateral load resisting systems in high seismicity regions. One of the common problems with the use of concentrically braced frames is limitationin the architectural application andposition ofthe openings. Two-story X bracedframes have more advantages than other configurations of concentrically braced frames, since in many cases the positionof the openings due to the needfor architectural spaces andexecutiveimperfections causes the use of asymmetric X-bracedframes, present study tries toevaluate the seismicbehavior ofasymmetric two-storyX braces. Inthis study, the behavior ofthese braces has been studied. Forthis purpose, firstly, several symmetric two-story X braced frames are modeled by OpenSees software. Then, by changing the position of braces to beam connection, the new asymmetrical braces are obtained which initially designed. Finally, parameters such as stiffness, strength and stable hysteresis cycle of asymmetric systems are compared with symmetrical braces by nonlinear static and dynamic analysis. The results showthat ifasymmetric braces are distributedsymmetricallyinthestructure,they donot lose their ability in comparison with the symmetrical models.