بررسی تأثیر حذف تغییرمکان ماندگار در زلزله‌های نزدیک گسل بر روی ساختمان-های چند طبقه

نوع مقاله : یادداشت پژوهشی

نویسنده

گروه عمران، دانشکده فنی مهندسی، دانشگاه ازاد اسلامی واحد اردبیل، اردبیل، ایران

چکیده

زلزله‌های حوزه نزدیک دارای دو اثر مهم هستند، جهت‌پذیری پیش‌رونده و تغییرمکان ماندگار که در آن جهت‌پذیری پیش‌رونده به جهت وقوع زلزله بستگی دارد و تغییر مکان ماندگار یا حرکت پرتابی بخاطر تغییر مکانهای ماندگار زمین در اثر تغییر شکلهای تکتونیکی و همراه شدن آن با مکانیزم پارگی به وجود می‌آید که با پالس سرعت با دامنه زیاد و یک گام یکنواخت در تاریخچه زمانی تغییر مکان همراه است. با توجه به اینکه مطالعات چندانی درباره اثرات تغییرمکان ماندگار روی سازه‌ها بر خلاف جهت‌پذیری پیش رونده انجام نشده‌است و همچنین در بیشتر مرکز اطلاعات رکوردها، تمامی زلزله‌ها با استفاده از روش‌های فیلتر کردن، فیلتر می‌شوند و اثر تغییر مکان ماندگار در آنها حذف می‌شود بنابراین در این تحقیق چهار نوع سازه 4، 8، 12و 16 طبقه انتخاب و برمبنای آیین‌نامه لرزه‌ای آمریکا(ASCE-10) و با رعایت کلیه معیارها و ضوابط در مورد قابهای خمشی ویژه در آیین نامه فولاد آمریکا(AISC341-10) طراحی می‌شوند.16 رکورد از رکوردهایی که دارای اثر تغییر مکان ماندگار هستند انتخاب و به سازه‌ها اعمال می‌گردند. همچنین برای اینکه اثرحذف تغییر مکان ماندگار و فیلترکردن روی پاسخ سازه‌ها مشخص شود همان 16 رکورد بصورت فیلتر شده به سازه‌ها اعمال و با حالت بدون فیلتر مقایسه می‌گردد. نتایج نشان داد که تغییر مکان ماندگار تأثیر چندانی در پاسخ سازه‌ها ندارد و می‌توان از رکوردهای فیلتر شده استفاده کرد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Effect of fling-step removal in near-fault earthquakes on multi-story buildings

نویسنده [English]

  • Bahram Rezayibana
Civil Engineering Department, Islamic Azad University , Ardabil Branch, Ardabil, Iran
چکیده [English]

Near-field earthquakes have two important effects, Forward Directivity and Fling-step, in which Forward Directivity depends on the direction of occurrence of an earthquake, and Fling-step happens due to permanent displacement of the earth due to tectonic deformations and its integration with the tearing mechanism with a velocity pulse with high amplitude and a uniform step in the displacement time history. Considering that few studies have been done on the effects of fling-step on structures other than Forward Directivity, and also in most earthquake data centers, all earthquakes are filtered using filtering methods and the fling-step effect is eliminated, therefore, four types of 4, 8, 12 and 16-story structures are selected and are designed based on the American Seismic Code (ASCE-10), in accordance with the American Steel Regulation (AISC341-10), in accordance with all the criteria for steel special moment frames. 16 records having fling-step effect are selected and applied to the structures. Also, to show effect of neglecting the fling-step on the response of the structures, the same records having no fling-step are applied to the structures and compared to the unfiltered state. The results showed that fling-step has little effect on the structure response, and filtered records can be used on seismic analysis.

کلیدواژه‌ها [English]

  • Fling-step
  • Forward Directivity
  • Near-Field Earthquake
  • Special Steel Moment Frames
  • Displacement
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