عنوان مقاله [English]
The coupling of individual wall piers via steel coupling beams has shown more lateral stiffness and strength than coupled shear wall systems with concrete beams. In order to obtain the desired behavior of these systems, the coupling beams must be sufficiently strong and stiff, yield before the wall piers, behave in a ductile manner, and exhibit significant energy absorbing characteristics. Therefore, the seismic response of coupled shear wall systems is strongly dependent on the hysteretic characteristics of coupling beams, and the evolution of the behavior of these beams is very important and necessary under cyclic loading. In this paper, in order to increase the structural performance of concrete coupled shear walls, a new and simple model of a steel coupling beam with a diagonal web stiffener is proposed, which can be used instead of conventional steel coupling beams with standard or vertical stiffeners, designed based on the Iranian code for steel structure design criteria. For validation of the coupled wall sub-assemblage model in this study, the finite element results were verified with experimental results using Abaqus 6.10.1 software. Then, a numerical study was done and the results were compared with the behavior of steel coupling beams with a standard stiffener. A collection of parametric studies on 30 models, with respect to two dimensionless parameters, under cyclic loading, was carried out. These two parameters were the web compactness ratio, i.e. ratio of height to the web thickness of the beam, and the horizontal diagonal stiffener angle. Analysis results show that a diagonal web stiffener is capable of increasing steel coupling beam performance, in terms of stiffness, strength, energy dissipation and, in some cases, rotation capacity, which lead to a decrease in the depth of the section. Furthermore, to achieve optimum performance, some different geometrical conditions for diagonal stiffeners were investigated and it was concluded that stiffeners should be installed at a 30-degree angle from the horizontal.