To evaluate the influences of the number of stories on the torsional response and ductility demand distribution in the plan and the height of plan asymmetric RC dual lateral load resistant multi-story buildings, three categories of structural models that contain 8-, 14- nd 20-stories buildings (with the wide range of eccentricity values) are subjected to an assemblage of ordinary and near-fault ground motions. The approach of modeling has been used, is more accurate for multi-storey R/C structures, because it redefines the stiffness from the strength in each time step. According to the findings, the torsional effects, decreases for high-rise structures where the lateral natural period increases.
In many buildings, the centers of resistance do not coincide with the centers of mass, resulting even for a purely translational excitation; the resultants of the stories resisting forces do not pass through the stories centers of mass. When these structures, so- called asymmetric buildings, are subjected to earthquake ground motion, they undergo both translational and rotational motion even though the earthquake excitation is purely uni-direction translational. Most of the conducted work on inelastic seismic response of asymmetric buildings are performed on simplified, highly idealized, one-storey models, with simple shear-beam elements (mostly three) esigned for lateral load resistance. Tso and Sadek (1985) employing such a models resulted that while the inelastic response s not mainly translational, the ductility demand of the edge lateral resisting elements could be increased up to twice of similar lements in the symmetric building. Effect of torsion on the stiff and flexible sides is a serious discrepancy in the pervious studies; some researches such as Tso and Ying (1990) and Mittal and Jain (1995) stated the inelastic torsional effects could lead to critical response in the flexible edge and are not important in the stiff edge, while Chandler and Duan (1991) explained that for the models they studied, a critical circumstance would occur in the stiff edge. Tso and Zhu (1992) in a separate study showed that these contradictory conclusions could be upon the type of models and assumptions used for their design and the type of eccentricity.
Publisher : Sixth National Congress on Civil Engineering
By : Amir M. Halabian , Mohammad S. Birzhandi
File Information: English Language/ 8 Page / size: 539 KB
سال : 1390
ناشر : ششمین کنـگره ملی مهنـدسی عمـران
کاری از : امیر محمد خلبان ، محمد سید بیرگندی
اطلاعات فایل : زبان انگلیسی / 8 صفحه / حجم : KB 539