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THIN-WALLED CROSS SECTION SHAPE INFLUENCE ON STEEL MEMBER RESISTANCE ABSTRACT: This work describes why trending thin-walled technology is achieving popularity in steel construction sector. A purpose of this article is to present the influence of the cold-formed element cross-section shape on an axial compression and a bending moment resistance. The authors have considered four different shapes assuming constant section area and thickness. Calculations were based on three different steel grades taking into account local, distortional and overall buckling. The results are presented in a tabular and a graphical way and clearly confirm that cross-section forming distinctly impact the cold-formed member resistance. The authors choose these cross-sections that work better in compression state and the other (those slender and high) that function more efficiently are subjected to bending. منبع دانلود THIN-WALLED CROSS SECTION.pdf

INVESTIGATING DURABILITY TIME INTERVAL OF THREE-DIMENSIONAL STEEL FRAME WITH ANGLE CONNECTIONS UNDER ELEVATED TEMPRATURE ABSTRACT: During recent years, much attention has been paid to the analysis of fire effect on steel structures because of fire importance and its effect on the stability of steel structures. Considering steel sensitivity to heat and high costs of steel frames retrofitting with the help of thermal covers, accurate behavior analysis of metal frames in elevated temperatures is required in order to reduce undesirable effects of temperature increase. To do so and taking into account the high costs of lab tests and their limitations in investigation of numerous parameters during any test, finite element method is used as a powerful and valuable tool in modeling of steel frames under thermal conditions. In this study, the fire effect on steel beams is studied considering the softening of connection and decrease of materials strength. Then, structure durability in fire will be analyzed in the ANSYS software. The analyzed frame is a single span three dimensional one and different conditions including connection type, longitudinal expansion effect, thermal loading and the kind of fire will be analyzed and compared. The obtained computer results will be compared with other researches results. منبع دانلود INVESTIGATING DURABILITY.pdf

Comparison of chevron and suspended-zipper braced steel frames Yigit Ozcelik a, Afsin Saritas b,⁎, Patricia M. Clayton a a Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX 78712, USA b Department of Civil Engineering, Middle East Technical University, Ankara 06800, Turkey a r t i c l e i n f o a b s t r a c t Article history: Received 22 June 2015 Received in revised form 14 November 2015 Accepted 8 December 2015 Available online xxxx a b s t r a c t Suspended-zipper braced frame is a modified configuration of chevron braced frame inwhich zipper columns are added between story beams and a hat truss is attached between top two stories in order to redistribute the unbalanced vertical forces emerging following the brace buckling to avoid the use of deep beams. In this study, three- and nine-story chevron and suspended-zipper braced frames are analyzed to compare their seismic performances. The beams, columns, braces and zipper columns are modeled using nonlinear force-formulation frame elements and nonlinear geometric effects are included by utilizing corotational transformation. Nonlinear static analyses are performed until reaching a roof drift ratio of 3% and a set of twenty ground motion records scaled to match a 10% probability of exceedance in 50 years is used for nonlinear time-history analysis. The results appear to indicate that the lateral load capacity and drift demands for both low-rise chevron and suspendedzipper braced frames are very similar; however, the mid-rise chevron braced frame has a better performance compared to the mid-rise suspended-zipper braced frame. © 2015 Elsevier Ltd. All rights reserved. Keywords: Steel structures Concentrically braced frames Chevron braced frames Suspended-zipper braced frames Nonlinear static analysis Nonlinear time-history analysis 10.1016_j.jcsr.2015.12.019-Comparison-of-chevron-and-suspended-zipper-braced-steel-frames.pdf

Seismic behavior of code designed steel plate shear walls Jeffrey W. Berman∗ Department of Civil and Environmental Engineering, University of Washington, Seattle, WA 98195-2700, United States Engineering Structures 33 (2011) 230–244 AbstractThe AISC Seismic Design Provisions now include capacity design requirements for steel plate shear walls, which consist of thin web plates that infill frames of steel beams, denoted horizontal boundary elements (HBEs), and columns, denoted vertical boundary elements (VBEs). The thin unstiffened web plates are expected to buckle in shear at low load levels and develop tension field action, providing ductility and energy dissipation through tension yielding of the web plate. HBEs are designed for stiffness and strength requirements and are expected to anchor the tension field formation in the web plates. VBEs are designed for yielding of web plates and plastic hinge formation at the ends of the HBEs. This paper assesses the behavior of code designed SPSWs. A series of walls are designed and their behavior is evaluated using nonlinear response history analysis for ground motions representing different hazard levels. It is found that designs meeting current code requirements satisfy maximum interstory drift requirements considering design level earthquakes and have maximum interstory drifts of less than 5% for maximum considered earthquakes. Web plate ductility demands are found to be significantly larger for low rise walls than for high rise walls where higher modes of vibrations impact the response. The percentage of story shear resisted by the web plate relative to the boundary frame is found to be between 60% and 80% and is relatively independent of panel aspect ratio, wall height, or hazard level, but is affected by transitions in plate thickness. Maximum demands in VBEs in design level shaking are found to be considerably less than those found from capacity design for SPSWs with 9 or more stories. Research highlights► Steel plate shear walls designed via current building code requirements meet drift limitations. ► Web plate ductility demands in low-rise steel plate shear walls are significantly larger than those in taller steel plate shear walls. ► The percentage of story shear resisted by the web plates was found to range from 60–80% and is independent of aspect ratio, wall height and seismic demand but is affected by transitions in web plate thickness. ► Maximum demands in steel plate shear wall columns from nonlinear response history analysis are found to be considerably less than those determined from capacity design in steel plate shear walls with 9 or more stories. Keywords Steel plate shear walls; Seismic behavior; Ductility; Seismic design; Column demands; Steel structures; Shear walls 10.1016_J.ENGSTRUCT.2010.10.015-Seismic-behavior-of-code-designed-steel-plate-shear-walls.pdf