تحلیل و طراحی بهینه ی پل‌های بتنی جعبه‌ای قطعه‌ای پیش‌ساخته با اجرای طره‌ای متعادل، مطالعه موردی: پل استقلال اصفهان

نوع مقاله : علمی - پژوهشی

نویسندگان

1 دانشجوی دکترای سازه، گروه مهندسی عمران، پردیس دانشگاه صنعتی اصفهان، اصفهان 83111- 84156، ایران

2 دانشیار دانشکده عمران، دانشگاه صنعتی اصفهان، اصفهان 83111- 84156، ایران

چکیده

در دهه‌های اخیر اجرای پل‌های بتنی پیش‌ساخته قطعه‌ای به خاطر عملکرد خوب و صرفه‌ی اقتصادی در دنیا عمومیت ‌یافته و رو به افزایش است. از آنجا که ساخت این پل‌ها برای دهانه‌های 50 تا 250 متر متداول است، در ردیف پروژه‌های بزرگ قرار می‌گیرند؛ لذا بهینه‌سازی آن‌ها می‌تواند منجر به صرفه‌جویی اقتصادی قابل‌توجهی گردد. در این مقاله با به‌کارگیری الگوریتم ژنتیک، هزینه‌ی روسازه‌ی این پل‌ها بهینه‌سازی شده است. مقطع عرضی پل قوطی شکل با عمق ثابت و روش اجرای طره‌ای متعادل در نظر گرفته ‌شده است. ارتفاع مقطع، ضخامت بال ها و جان ها و نیز تعداد کابل‌های پیش تنیدگی به ‌عنوان متغیرهای طراحی در نظر گرفته ‌شده‌اند. محدودیت‌های تنش مجاز در مراحل مختلف اجرا به همراه قیود مقاومت نهایی خمشی و برشی، قید خیز و قیود هندسی بر اساس آیین‌نامه های آشتو استاندارد و آشتو LRFD در بهینه‌سازی اعمال‌شده‌اند و الگوریتم بهینه‌سازی، تحلیل و طراحی سازه پس از نگارش در نرم‌افزار Matlab اجرا شده است. پل استقلال اصفهان (بهره‌برداری شده در سال 1396) به‌عنوان پل مورد مطالعه انتخاب شده و مقایسه‌ی نتایج طراحی بهینه‌ی آن با طرح اجرا شده‌ی پل، حاکی از صرفه‌جویی 13 درصدی در هزینه و وزن روسازه می‌باشد. همچنین با بهینه سازی این گونه پل‌ها در دهانه های مختلف، رابطه ی بین هزینه با طول دهانه مورد بررسی قرار گرفته است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Analysis and Optimal Design of Segmental Precast Concrete Bridges with Balanced Cantilever Construction (Case Study: Esteghlal Bridge in Isfahan)

نویسندگان [English]

  • Reza Ghiamat 1
  • Morteza Madhkhan 2
1 Civil Engineering group, Pardis College, Isfahan University of Technology, Isfahan 84156-83111, Iran
2 Department of Civil Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran
چکیده [English]

The construction of segmental precast concrete bridges is an increase due to its superior performance and economic advantages. This type of bridge is appropriate for spans within 50 to 250 m, known as mega-projects and the design optimization would lead to considerable economic benefits. In this study, a box-girder cross section of bridge superstructure with balanced cantilever construction method is assessed. The depth of cross section, thickness of top and bottom flange, thickness of webs and the count of strands of pre-stressed steel are considered as design variables. The optimum design is characterized by geometry, serviceability, ductility, and ultimate limit states specified by the American Association of State Highway and Transportation Officials (AASHTO) standard and AASHTO Load and Resistance Factor Design (LRFD) specifications. Genetic algorithm (GA) is applied for cost and weight optimization. To validate functionality of this algorithm, a real bridge constructed in the city of Isfahan, Iran (Esteghlal Bridge, completed in 2017) is optimized as a case study. The total of a 13% reduction in cost and weight of the bridge superstructure is observed. The cost optimization algorithm is run by considering different spans and relation between superstructure cost and span length is assessed. The efficiency of applying the GA in optimization of this kind of bridges is proved.

کلیدواژه‌ها [English]

  • optimization
  • Segmental Concrete Bridge
  • Box girder
  • Balanced Cantilever
  • Genetic Algorithm
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