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 ...

The design of tall buildings essentially involves a conceptual design, approximate analysis, preliminary design and optimization, to safely carry gravity and lateral loads. The design criteria are, strength, serviceability, stability and human comfort. The strength is satisfied by limit stresses, while serviceability is satisfied by drift limits in the range of H/500 to H/1000. Stability is sat...

Controlled rocking of steel braced frames has been proposed for the seismic retrofit of structures. The controlled rocking approach allows a frame to uplift from its support at the base-of-column to foundation interface while displacementbased steel yielding devices are implemented at the base location to control the response. Past studies have focused on analytical investigations of the respon...

Controlled rocking of steel braced frames has been proposed for the seismic retrofit of structures. The controlled rocking approach allows a frame to uplift from its support at the base-of-column to foundation interface while displacement-based steel yielding devices are implemented at the base location to control the response. Past studies have focused on analytical investigations of the respo...

Conventional seismic rehabilitation methods may not be suitable for some buildings owing to their high cost and time-consuming foundation work. In recent years, viscoelastic dampers (VEDs) have been widely used in many mid- and high-rise buildings. This study introduces a viscoelastic passive control system called rotary rubber braced damper (RRBD). The RRBD is an economical, lightweight, and e...

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) ...

current innovative lateral load carrying systems for tall buildings are those in which the lateral drift is limited to an allowable value without considerable influence on economy. this aim is achieved by using special systems capable of using maximum stiffness and strength capacity of individual structural elements. an effective structural solution in this respect is the use of outrigger brace...

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...

The objective of this paper is to describe and analyze a series of nonlinear finite element analyses used to compare three design methods for locally slender, braced, steel beams and columns. The three design methods are: (i) the hot-rolled steel AISC Specification, (ii) the coldformed steel AISI Specification which uses the effective width method throughout, and (iii) the cold-formed steel Dir...