ارزیابی آسیب پذیری لرزه ای ساختمان های بتن آرمه مقاوم سازی شده با روش ژاکت فولادی ستون ها به روش احتمالاتی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار گروه سازه و زلزله دانشکده عمران، دانشگاه صنعتی شاهرود

2 دانشجوی دکترای عمران سازه، دانشگاه صنعتی نوشیروانی بابل، ایران

3 کارشناسی ارشد مهندسی عمران، موسسه آموزش عالی پردیسان مازندران

چکیده

در این تحقیق با انجام مطالعات میدانی وسیع در ساختمان های ساخته شده شمال کشور با بررسی ضعف های متعارف اجرایی، عملکرد لرزهای ساختمان های بتن آرمه با سیستم قاب خمشی کوتاه، متوسط و بلند مرتبه بررسی گردید. ضعف سازهای از جمله مقاومت کم بتن و طول نا کافی وصله میلگردهای ستونها در مدلسازیها در نظر گرفته شد. مدلها به صورت سه بعدی تحت بیست رکورد دور از گسل زلزله در نرم افزار اوپنسیس تحلیل دینامیکی غیرخطی فزاینده شدند. سپس به روشهای احتمالاتی و با در نظر گیری عدم قطعیتهای موثر شامل مقاومت بتن و مشخصات زلزله، احتمال آسیب پذیری لرزه ای و منحنی شکنندگی این ساختمانها ترسیم گردید. در گام بعدی ستونهای سازهها با استفاده از ژا کت فولادی مقاوم سازی شدند و میزان خسارت لرزه ای آنها در سطوح عملکردی مختلف به کمک منحنی های شکنندگی لرزه ای بدست آمد. با مقایسه مقادیر میانه شکنندگی لرزه ای مدلهای دارای ضعف سازه ای و مدلهای مقاوم سازی شده مشاهده گردید که در ساختمان های مورد بررسی مقادیر میانه شکنندگی لرزه ای بطور چشمگیری در مدلهای مقاوم سازی شده افزایش یافته است. ضمنا مشاهده گردید که اثربخشی روش مقاوم سازی در نظر گرفته شده علاوه بر سطح آسیب به تعداد طبقات ساختمان نیز بستگی دارد.

کلیدواژه‌ها

عنوان مقاله [English]

Probabilistic Seismic Vulnerability assessment of RC Frame Structures Retrofitted with Steel Jacketing

نویسندگان [English]

  • hossein pahlavan 1
  • ali naseri 2
  • armin einolahi 3
1 Assisstant Professor of Earthquake Engineering, Shahrood University of Technology
2 Ph.D. Candidate of Structural Engineering, Babol Noshirvani University of Technology
3 Msc. student of Structural Engineering, University of Pardisan, Mazandaran.
چکیده [English]

A majority of Iranian residential buildings have Reinforced Concrete (RC) frame structures with intermediate ductility. Recent earthquakes have revealed major seismic deficiencies in these buildings, some of which led to catastrophic collapses and significant death tolls. Causes for the unsatisfactory performance include the absence of special seismic detailing of key structural elements, inadequate material and construction quality. Based on an extensive field investigation done by the authors on the short, mid-rise and high-rise Northern Iranian as-built structures having RC frames, in this study, reduced strength of concrete and also insufficient overlap length of column’s longitudinal bars are considered as common structural deficiencies and then by considering probable uncertainties such as material and earthquake uncertainty, the seismic performance of considered buildings are developed via fragility curves based on probabilistic method. For generation of seismic fragility curves for as built and also retrofitted models, 3 dimensional analytical models analyzed based on Incremental Dynamic Analysis (IDA) in OpenSEES. The demand statistics in terms of maximum inter– story drift ratio are obtained for 20 sets of ground motion records and the capacity is determined according to the HAZUS-MH limit states and finally the corresponding fragility curves for four damage states are developed for as built and retrofitted models. The results represent the effect of the story numbers, structural deficiency and implemented retrofit strategy on the seismic vulnerability of this subclass of structures.

کلیدواژه‌ها [English]

  • Seismic Vulnerability
  • Retrofit
  • Steel Jacket
  • Fragility curve
  • OpenSEES

مراجع

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نشریه مهندسی عمران امیرکبیر
دوره 51، شماره 3
مرداد و شهریور 1398
صفحه 585-598

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