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NUMERICAL STUDY OF OPENING EFFECT ON SEISMIC BEHAVIOR OF UN-STIFFENED STEEL SHEARWALL

Steel shear wall system is used as one of main resisting systems against lateral loads. Sometimes due to architectural needs, opening has to be considered in the walls. Thus, it is necessary to study its effect on seismic behavior of the shear wall. Therefore in this paper, steel shear walls of 2mm, 4mm and 6mm thick plates were modeled in 4 and 7 story frames using ANSYS software., subjected to push-over analysis where its seismic parameters were obtained by Uhang method. To investigate the impact of opening, 700x400mm, 900x600mm, 1100x800mm and 1600x1000mm openings were assumed in the center and corner of the shear walls. Based on the obtained results, opening is suitable to be in the center rather than in the corners. Also for the steel shear walls having un-stiffened rectangular openings h/tw is better to be between 500 and 750. Moreover, opening size is recommended to be from 2% to 6.5%. Strength and stiffness degradation is mostly dependent on the plate thickness rather than the opening size. In overall, even a small opening reduces a major portion of strength and stiffness.