تحلیل شکنندگی لرزه ای پل های قوسی بتنی چند قابی جداسازی شده با جداگر لرزه ای

نوع مقاله : علمی - پژوهشی

نویسندگان

1 خیابان افریقا نبش کوچه سپر پلاک 24

2 استادیار گروه سازه و زلزله، دانشگاه صنعتی شاهرود، دانشکده مهندسی عمران، شاهرود، ایران

3 استاد گروه عمران دانشگاه پردیسان مازندران

4 دانشکده فنی و مهندسی دانشگاه دامغان ، دامغان ، ایران

چکیده

پل‌ها به عنوان یکی از اصلی‌ترین و آسیب‌پذیرترین سازه‌ها در شریان‌های حیاتی هر‌کشور محسوب می‌شوند. از طرف دیگر به دلیل رفتار دینامیکی پیچیده ای که پل‌های قوسی ناشی از شرایط هندسی خاص در زلزله از خود نشان می‌دهند در این تحقیق مقاوم سازی اینگونه از پل‌ها مورد مطالعه قرار گرفت. بنابراین دو مدل پل عرشه جعبه‌ای شکل بتن‌آرمه دارای قوس افقی با شعاع های یکسان در دو حالت با جداساز لرزه‌ای و بدون جداساز مورد ارزیابی قرار گرفت. به طوری که کفایت استفاده از جداساز لرزه‌ای هسته سربی در مقایسه با حالت بدون جداساز لرزه ای توسط منحنی های شکنندگی بررسی شد و سطوح خسارات لرزه‌ای محتمل بدست آمده‌اند. نتایج پژوهش با مدل‌سازی پل در نرم‌افزار المان‌محدود CSi Bridge تحت تحریک 100 زوج شتاب نگاشت واقعی تحت تحلیل تاریخچه‌زمانی غیرخطی قرار گرفته و پاسخ المانها از آن استخراج شده‌است. بطوریکه متوسط حداکثر جابجایی نسبی در مدل با جداساز لرزه‌ای نسبت به حالت بدون جداساز لرزه‌ای در جهت طولی و عرضی به ترتیب 67 و 64 درصد کاهش یافته است. ضمناً در پی انجام تحلیل مودال و مقایسه زمان تناوب پل‌ها، مشاهده می‌شود زمان تناوب اول تا سوم ارتعاش پل ها درحالت با جداگر نسبت به حالت بدون جداگر با افزایش قابل توجه‌ای مواجه بوده است. نتایج این پژوهش حکایت از آن داشته که در این دسته از پل‌ها استفاده از جداگر لرزه‌ای بطور چشم گیری موجب کاهش جابجایی نسبی ستونها شده بطوریکه شکنندگی لرزه‌ای سیستم پل در سطوح آسیب مختلف کاهش یافته ‌است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Seismic fragility analysis of multi-frame RC curved bridges with base isolation

نویسندگان [English]

  • Meysam Balou 1
  • Hossein Pahlavan 2
  • Ali Naseri 3
  • fshime rafiee 4
1 خیابان افریقا نبش کوچه سپر پلاک 24
2 Assistant Professor, Faculty of Civil Engineering, Shahrood University of Technology, Iran
3 Instructor , Faculty of Civil Engineering, Pardisan university, mazandaran
4 Faculty of Engineering, Damghan University, Damghan, Iran
چکیده [English]

Bridges are counted as one of the most important and vulnerable structures in the vital veins of every country. The abundance of the concrete box deck bridges with concrete arches on the one hand, and the complex dynamic behavior resulted from special geometric conditions of this class of bridges which have made them more vulnerable on the other hand, were aimed to be studied in this research. In this study, a model of a concrete box deck bridge with concrete arches and the appropriateness of using lead-rubber bearing system were examined, and ultimately, two states of the bridge with and without seismic isolation were assessed by fragility curves, and the amount of possible seismic damage have been obtained. The study results were analyzed by modeling the bridge in the CSi Bridge finite-element software in three dimensions and under the excitation of 100 pairs of real accelerogram and under nonlinear time-history analysis, and the responses of the elements were extracted. So that, compared to the state without seismic isolator, the maximum relative displacement in the model with seismic isolator has decreased by 55 and 28 percent in the longitudinal and transverse directions; respectively. Also , based on the result of modal analysis and comparison of t the vibration period, the results show a significant increase in the first to third period of vibration of bridges in the state with seismic isolation compared to the without seismic isolation. The results of studies indicate that In this bridges with seismic isolation have reduced the drift of columns significantly so that the seismic fragility of the bridge system has been reduced at different levels of damage.

کلیدواژه‌ها [English]

  • &bull
  • RC curved bridge
  • LRB base isolation
  • Vulnerability assessment
  • Fragility curve
  • Nonlinear time-history analysis
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