تأثیر خاک بر تحلیل رفتار لرزه ای عملکردی سازه های بتن مسلح

نوع مقاله : علمی - پژوهشی

نویسندگان

1 کارشناسی ارشد مهندسی عمران، گروه مهندسی عمران، واحد بوشهر، دانشگاه آزاد اسلامی، بوشهر، ایران

2 استادیار، گروه مهندسی عمران، واحد بوشهر، دانشگاه آزاد اسلامی، بوشهر، ایران

3 استادیار، گروه مهندسی عمران، دانشگاه خلیج‌فارس، بوشهر، ایران

چکیده

چکیده

در گزارش FEMA-P695 یک روش کاربردی جهت ارزیابی فروریزش سازه های طراحی شده توسط آیین نامه های لرزه ای تحت شدیدترین زلزله مورد انتظار موجود می‌باشد و در آن فروریزش قاب های بتنی ویژه بدون در نظرگرفتن اثر اندرکنش خاک - سازه مورد مطالعه قرار گرفته است. در این مطالعه از تحلیل اندرکنش خاک - سازه به روش مستقیم برای ارزیابی عملکرد لرزه ای ساختمان ها استفاده می‌شود. برای این منظور از ساختمان های بتن مسلح 4 و 8 طبقه با سیستم قاب خمشی ویژه، بر روی خاک های متوسط (D) و نرم (E) طبقه بندی شده مطابق آیین نامه ASCE7-10، توسط نرم افزار Opensees مدل سازی و تحلیل شده اند. از آنالیز دینامیکی افزاینده جهت بررسی دقیق عملکرد فروریزش قاب ها برای دو حالت پایه صلب و پایه انعطاف پذیر استفاده شده است. نتایج تحلیل نشان می‌دهد که اندرکنش خاک - سازه، به خصوص با نرم تر شدن خاک و افزایش تعداد طبقات ساختمان، می‌تواند نقشی اساسی در رفتار قاب های ساختمانی شامل افزایش پریود سیستم، کاهش دریفت طبقات، افزایش سطح عملکرد و تغییر احتمال فروریزش سازه ایفا نماید. از طرفی نتایج حاصله در نگاه اول نشان دهنده افزایش احتمال فروریزش برای قاب های قرار گرفته بر روی تکیه گاه های انعطاف پذیر در شتاب طیفی یکسان می‌باشد، اما با استفاده از منحنی شکنندگی انعطاف پذیر اصلاح شده مشاهده می‌شود که در نظر گرفتن اندرکنش خاک - سازه سبب کاهش احتمال فروریزش می‌شود. لذا عدم درنظر گرفتن اندرکنش خاک - سازه منجر به ارزیابی غیر واقعی عملکرد سازه ها می‌گردد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

The effect of soil on seismic performance analysis of reinforced concrete structures

نویسندگان [English]

  • Mehdi Zangouei 1
  • Hadi Dashti 2
  • Alireza Fiouz 3
1 M.Sc. of Civil Engineering, Department of Civil Engineering, Bushehr branch, Islamic Azad University, Bushehr, Iran
2 Assistant Professor, Department of Civil Engineering, Bushehr branch, Islamic Azad University, Bushehr, Iran
3 Assistant Professor, School of Engineering, Persian Gulf University, Bushehr, Iran
چکیده [English]

ABSTRACT

In the FEMA-P695 report, there is an applied method for evaluating the collapse of structures designed by seismic regulations under the most severely expected earthquake, in which the collapse of special concrete frames without considering the effect of soil-structure interaction is studied. In this study, soil-structure interaction analysis is used directly to evaluate the seismic performance of buildings. For this purpose, 4 and 8-storey reinforced concrete buildings with special bending frame system, on medium (D) and soft (E) soils classified according to ASCE7-10, have been modeled and analyzed by Opensees software. Incremental dynamic analysis has been used to accurately evaluate the collapse performance of the frames for both rigid base and flexible base. The results of the analysis show that the soil- structure interaction, especially with softer soil and increasing the number of building floors, can play a key role in the behavior of building frames including increasing system period, reducing floor drift, increasing performance and changing probability collapse of the structure. On the other, the results at first glance show an increase in the probability of collapse for frames placed on flexible supports at the same spectral acceleration, but using the modified flexible fragility curve, it is observed that the soil-structure interaction reduces the likelihood of collapse. Therefore, not considering the soil-structure interaction leads to unrealistic evaluation of the performance of structures.

کلیدواژه‌ها [English]

  • RC special frame
  • Collapse
  • Incremental dynamic analysis (IDA)
  • Soil-structure interaction (SSI)
  • Direct method
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