Nonlinear Seismic Performance of RC Structures with Different Floor by Capacity Spectrum Method

Document Type : Original Article

Author

Professor, Faculty of Civil Engineering, Semnan University, Semnan, Iran

Abstract

Civil engineering structures as well as office or apartment building are affected by earthquakes. In some buildings, few or no walls are provided at the first story (pilot). In the structures with difference in story level, major problems is due to discontinuity of floor diaphragm that causes significant changes in period, stiffness and distribution of earthquake force. In this paper, using linear and nonlinear static analysis, time history and location of plastic hinge in short columns and beams, period, displacement, shear force, performance point and capacity spectrum and…, in 2, 4, 6, 8, and 10 story structures with story level difference are studied. The results show that the effect of level difference in short structures is obvious and by increasing the height difference, the effect of short column phenomenon is decreased and the performance point is increased.
ملاحظات معماری از قبیل قرارگیری پیلوت و واحدهای تجاری در همکف، جلوگیری از تجمّع ورودی‌های مختلف در مجتمع‌های آپارتمانی، سازه‌های دوبلکسی را پدید می‌آورد که در آن‌ها کف‌های طبقات با اختلاف ترازی نسبت به هم در دو یا چند تراز ارتفاعی مختلف ایجاد می‌شوند. در سازه‌های دوبلکسی عمده مشکلات ناشی از عدم پیوستگی دیافراگم کف می‌باشد که باعث تغییرات چشم‌گیری در دوره تناوب، سختی و پخش نیروی زلزله می‌گردد. در این مقاله با آنالیز استاتیکی خطی و غیرخطی به بررسی موقعیت مکانی و زمانی وقوع اولین مفصل پلاستیک در تیرها و ستون‌های کوتاه، دوره تناوب، تغییر مکان، نیروی برشی، نقطه عملکرد و طیف ظرفیت و... در پنج سازه دوبلکسی 2، 4، 6، 8 و 10 طبقه پرداخته‌شده است. نتایج نشان می‌دهد که اثر اختلاف تراز در سازه‌های کوتاه مشهودتر بوده و با افزایش ارتفاع اثر پدیده ستون کوتاه در سازه‌های دوبلکسی کاهش و نقطه عملکردی آن افزایش می‌یابد.

Keywords

Main Subjects

References

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History

  • Receive Date: 30 May 2017
  • Revise Date: 05 September 2017
  • Accept Date: 28 November 2017

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