Seismic Behavior of Asymmetric Two-Story X-braced Frames

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 limitation in the architectural application and position of the openings. Two-story X braced frames have more advantages than other configurations of concentrically braced frames, since in many cases the position of the openings due to the need for architectural spaces and executive imperfections causes the use of asymmetric X-braced frames, present study tries to evaluate the seismic behavior of asymmetric two-story X braces. In this study,  the behavior of these braces has been studied. For this 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 show that if asymmetric braces are distributed symmetrically in the structure, they do not lose their ability in comparison with the symmetrical models.

Keywords:

Asymmetric Two-Story X-braced Frames , Concentrically Braced Frames , Seismic Performance , Hysteresis Cycle , Ductility