ارزیابی احتمالاتی آسیب‌پذیری لرزه‌ای قاب‌های خمشی بتن‌آرمه در معرض خوردگی

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی، تهران، ایران

چکیده

زلزله­ ها و آسیب­ های ناشی از شرایط محیط خورنده، دو عامل مهمی هستند که عملکرد مطلوب سازه­ ها را در شهرهای ساحلی خلیج فارس در جنوب ایران تهدید می­ کند. لحاظ نمودن هر دوی این خطرها در آنالیز و طراحی سازه­ ها می‌تواند ضمن کاهش تلفات جانی، صرفه جویی­ های فراوان اقتصادی را به دنبال داشته باشد. در سال‌های اخیر، مطالعات در زمینه ارزیابی احتمالاتی آسیب­ پذیری لرزه ­ای سازه­ ها رو به گسترش بوده است. در این مقاله از رویکرد ریسک-محور برای ارزیابی لرزه ­ای قاب ­های بتن ­آرمه خمشی با شکل‌پذیری متوسط که در معرض آسیب‌های ناشی از خوردگی پایه-کلرایدی میلگردهای طولی در 4 شهر بندری مهم جنوب ایران (شامل بوشهر، عسلویه، بندرعباس و چابهار) قرار دارند، استفاده گردید. در مجموع 18 قاب خمشی بتن ­آرمه با تعداد طبقات متفاوت و در بازه‌های زمانی 10 ساله پس از آغاز خوردگی، مورد تحلیل دینامیکی فزاینده (IDA) قرار گرفتند. سپس با استفاده از انتگرال ریسک، احتمال فروریزش سالانه برای قاب­ ها در شهرهای مورد مطالعه به دست آورده شده و مورد ارزیابی قرار گرفت. نتایج این مطالعه نشان می ­دهد که با گذشت زمان پس از آغاز خوردگی، احتمال فروریزش سازه ­ها به شدت افزایش می‌یابند که نشان دهنده لزوم بالای استفاده از فرآیند ریسک-محور برای ارزیابی و طراحی لرزه ­ای سازه­ هایی است که در معرض آسیب‌های ناشی از محیط‌های مهاجم قرار دارند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Probabilistic seismic vulnerability assessment of reinforced concrete moment frames exposed to corrosion

نویسندگان [English]

  • Morteza Khademi
  • Mohammad Reza Mansoori
  • Mirhamid Hosseini
department of civil Engineering, Islamic Azad University, Science and research branch
چکیده [English]

Earthquakes and damages caused by corrosive environmental conditions are two important factors that threaten the desirable performance of structures in the coastal cities of the Persian Gulf in southern Iran. Taking into account both of these risks in the analysis and design of structures can reduce the loss of life and can lead to significant economic savings. In recent years, studies on the probabilistic seismic vulnerability assessment of structures have been developed. In this paper, a risk-based approach is used for seismic evaluation of reinforced concrete moment frames with medium ductility that are exposed to damage due to chloride-based corrosion of rebars in 4 important port cities of southern Iran (including Bushehr, Assaluyeh, Bandarabbas and Chabahar). A total of 18 reinforced concrete moment frames with different number of stories and in increments of 10 years after the initiation of corrosion, were subjected to incremental dynamic analysis (IDA). Then, using the risk integral, the annual probability of collapse for frames in the studied cities was obtained and evaluated. The results of this study show that over time after the initiation of corrosion, the probability of collapse of structures increases sharply, which indicates the high need for risk-based approach to evaluate and seismic design of structures that are exposed to damages due to aggressive environments.

کلیدواژه‌ها [English]

  • Probability of collapse
  • Risk-based seismic evaluation
  • Reinforced concrete moment frame
  • ‎Chloride-based Corrosion of reinforcement rebars
  • ‎Important port cities of southern Iran
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