in this study, for evaluating ductility of ordinary concentrically braced frames (ocbfs) and special concentrically braced frames (scbfs) which are x- braced in two adjacent middle spans, 16 steel ordinary concentrically braced frames and 16 special concentrically braced frames are studied. the results confirm that, although most of ordinary concentrically braced frames, which are x-braced, can...

In this study, topology optimization is applied to concentrically braced frames in order to find economical solutions for conventional structural steel frames. Differential Evolution Algorithm and Dolphin Echolocation Optimization are applied for structural optimization. Numerical examples are studied and results of comparison with other meta-heuristic algorithms, including Genetic Algorithm, A...

This paper presents a practical methodology for optimization of concentrically braced steel frames subjected to forward directivity near-fault ground motions, based on the concept of uniform deformation theory. This is performed by gradually shifting inefficient material from strong parts of the structure to the weak areas until a state of uniform deformation is achieved. In this regard, to ove...

response modification factor (r-factor) is one of the seismic design parameters to consider nonlinear performance of building structures during strong earthquake. relying on this, many seismic design codes led to reduce earthquake loads imposed to the structure. the present paper tries to evaluate the r-factors of conventional concentric braced frames (cbfs) and special moment frames (mrfs) in ...

Different expressions have been developed to determine damping of structures based on various hysteretic models and ductility levels. Since Slenderness ratio is an important parameter on the hysteretic behavior of special concentrically- braced frames (SCBF), in this paper new expressions for determination of damping of such frames are developed based on slenderness ratio and ductility. Two typ...

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 th...

This paper proposes a simplified analytical model for seismic response prediction of concentrically braced frames. In the proposed approach, a multistory frame model is reduced to an equivalent shear-building one by performing a static pushover analysis. The conventional shear-building model has been improved by introducing supplementary springs to account for flexural displacements in addition...

steel structures are usually built with some defects. according to the standard building codes, the central axes of the bracing members should go through the beam-column joints, however, in most of the braced steel structures, bracing members are unintentionally connected eccentrically. this paper presents a numerical investigation on performance analysis of cbfs (concentrically braced frames) ...