مهندسی سازه و ساخت

مهندسی سازه و ساخت

ارزیابی راهکارهای بهسازی سازه‌های بنایی غیرمسلح با استفاده از معیارهای کمی- احتمالاتی تصمیم‌گیری (مطالعه ی موردی مدارس ابتدایی واقع در شهر تهران)

نوع مقاله : علمی - پژوهشی

نویسندگان
1 استادیار-دانشکده مهندسی عمران و محیط زیست- دانشگاه صنعتی امیرکبیر (پلی تکنیک تهران)- تهران-ایران
2 دانشکده مهندسی عمران- دانشکده سمنان- سمنان- ایران
3 استاد، دانشکده ساخت و محیط زیست، گروه مهندسی عمران، دانشگاه متروپولیتن اسلو (اسلومت)، اسلو، نروژ
چکیده
این پژوهش به دنبال ارزیابی راهکارهای بهسازی در سازه‌های بنایی غیرمسلح براساس معیارهای احتمالاتی شامل خسارت مالی، وقفه در سرویس‌دهی، میزان مرگ و میر و تعداد مصدومین می‌باشد. مدل‌سازی براساس روش ماکرو قاب معادل اصلاح شده و مشخصات سازه‌ی انتخابی براساس ساختمان تیپیک کوتاه مرتبه مدرسه ابتدایی و راهکارهای بهسازی شامل استفاده از کلاف‌های قائم و افقی و کاهش درصد بازشوها می‌باشد. انتخاب رکوردها بر مبنای الگوی پیشنهادی براساس کمینه سازی انحراف معیار انجام شده است. نمودارهای شکنندگی سازه‌ای دیوارهای بنایی غیرمسلح برای سطوح خرابی بدون فروریزش و فروریزش مجموعا در سه سطح خرابی و جهت اعضای غیرسازه‌ای براساس نمودارهای پیش فرض بدست آورده شده است. مقادیر نرمال هر یک از گروه‌های عملکردی براساس احتمال مشاهده در نیمی از ساختمان‌های با کاربری مشابه و میزان تلفات جانی احتمالی براساس الگوی توزیع جمعیتی مدارس ابتدایی در نظر گرفته شده است. با اجرای راهکارهای بهسازی، میانه‌ی خسارت کاهش قابل توجهی معادل با 48% را نشان می‌دهد. کاهش در خسارت‌های کوچک، بیشتر از خسارت های بزرگتر متناسب با درصد احتمال تجمعی رویداد بیشتر بوده و نشان می‌دهد آورده‌ی مقاوم‌سازی در عمر مفید سازه بیشتر در زلزله‌های با شدت کم بدست می‌آید و در سطح فروریزش، کمترین کاهش در خسارت در اثر اعمال راهکارهای مقاوم‌سازی دیده می‌شود. اجرای راهکارهای بهسازی، سبب ایجاد کاهش تقریبا یکسانی در محدوده‌های احتمالاتی مختلف، معادل 51% کاهش در میانه‌ی زمان تعمیرات گردیده است. احتمال وجود مرگ و میر تحت محدوده‌ی گسترده‌ای از ضرایب هم‌پایه‌سازی رکوردها، پیش و پس از بهسازی به ترتیب برابر با 13% و حدود 2/5% می باشد که نشان دهنده‌ی تاثیرگذار بودن بهسازی بر این احتمال با وجود ساده و رایج بودن راهکارها می‌باشد. اجرای این راه کارها بر روی درصد اولیه‌ی مصدومین در احتمال‌های پایین رویداد تاثیر چندانی نداشته اما در احتمال‌های بالا سبب کاهش در تعداد مصدومین شده است.
کلیدواژه‌ها

موضوعات


عنوان مقاله English

Evaluation of rehabilitation strategies of non-reinforced masonry structures using quantitative-probabilistic decision-making criteria (case study of elementary school's of Tehran)

نویسندگان English

Leila Haj Najafi 1
Ali Kheyroddin 2
Mahdi Kioumarsi 3
1 َAssisstant Professor, Department of Civil and Environmental Engineering, Amirkabir University of Technology (Tehran , Polytechnic), Tehran, Iran.
2 Professor, Department of Civil Engineering. Semnan University, Semnan, Iran.
3 Prefessor, Department of Built Environment, Civil Engineering Group, Oslo Metropolitan University , Oslo,, Norway.
چکیده English

This research evaluates retrofitting strategies in unreinforced masonry structures using probabilistic criteria such as repair costs, downtimes, and number of casualties and injuries. The structure specifications are based on a typical short elementary school building modeled by the modified macro-element equivalent frame method. Retrofitting strategies include vertical and horizontal coils and reducing wall openings. Record selection follows a method aimed at minimizing standard deviation. This study derived structural fragility functions for unreinforced masonry walls, addressing both non-collapse and collapse scenarios across three damage states. For nonstructural components, the suggested default curves were utilized. The normative values for each functional group were determined based on their occurrence likelihood in half of the buildings with similar occupancy, along with the potential number of casualties derived from primary schools’ population distribution. Implementation of retrofitting strategies results in a notable decrease in average damage of 48%. The reduction in small damage levels surpasses that of more severe damage levels when considered concerning the cumulative occurrence probability percentage. It shows that the advantages of retrofitting, in terms of the useful life of structures are primarily realized during low-intensity seismic events. At the collapse level, the least damage reduction was seen due to retrofitting. Retrofitting strategies have led to a significant reduction in average repair time, with a 51% decrease observed. The probability of death has also decreased from 13% to about 2.5% after retrofitting, exhibiting the effectiveness of retrofitting strategies despite their simplicity and prevalence. While the strategies may not have affected initial injury percentages in low event probabilities, they have reduced the number of injuries in high-occurrence scenarios.

کلیدواژه‌ها English

Unreinforced Masonry Buildings
Fragility Function
Cost of Damage
Repair time
Downtime
Casualties
Injuries
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  • تاریخ دریافت 17 دی 1403
  • تاریخ بازنگری 28 اسفند 1403
  • تاریخ پذیرش 05 اردیبهشت 1404