مهندسی عمران شریف (Feb 2019)
APPLICATION OF STEEL PLATE SHEAR WALL AND TENSION-BRACING IN RETROFITTING OF STRUCTURES
Abstract
A rehabilitation technique that utilizes a thin steel plate as a supplemental shear wall system for steel moment frames is described. In the proposed system, the plate and surrounding boundary elements are installed in the middle of the bay, separate from existing columns (SW-TB =Steel Plate Shear Wall with Tension-Bracing). This geometry intends to reduce the forces transferred to the existing columns. In this paper, the behavior of steel moment frames using the proposed system is investigated. Among the methods of retrofitting of the steel frames, application of steel bracing system has been studied by some researchers. The results of these studies show that retrofitting of steel frames by adding braces has disadvantages such as increasing axial forces in adjacent columns, brittle behavior in the frame joints, buckling the bracing member, and creating a permanent deformation on the frame. In order to remove these disadvantage researches such as the use of non-compression brace, buckling-restrained braces, dissipative bracing systems, displacement-restraint bracing and thin infill panels are examined. Steel plate shear wall systems have attracted more attention in the past few years as one of the major lateral-load resisting system in steel buildings. In this context, many investigations have been conducted in different countries. In this study, to eliminate the above-mentioned disadvantages, a SW-TB system is used to retrofitting of a steel frame. Recent researches indicate that this type of shear walls has a very good performance in comparison to its traditional form (i.e., SSW= Steel Plate Shear Wall). For this purpose, the Finite-Element Model (FE) of steel frame retrofitted with steel shear walls and tension-bracing has been made. The obtained results of this model are compared with Laboratory data. The comparison shows that the finite-element model produces similar results to those of the proposed method in the laboratory. After the experimental validation, this method is compared with three other methods. The FE analysis results show that using this method causes the lateral resistance of the structure to increase as much as 50 percent with good ductility, and the need to enhance the lateral columns and foundations will be limited.
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