بررسی رفتار غیر خطی قاب های خمشی بتنی تقویت شده با دستک فلزی در خرابی پیش رونده

نوع مقاله : علمی - پژوهشی

نویسندگان

گروه مهندسی عمران، واحد زنجان، دانشگاه آزاد اسلامی، زنجان، ایران

چکیده

تخریب پیش رونده یک پدیده غیرخطی است که از آسیب دیدگی قسمتی از سازه شروع شده و به کل سازه و تخریب کلی آن ختم می شود. لذا بررسی این پدیده در سازه‌های بلند مرتبه و با اهمیت ضمن ایمن کردن آن باعث اطمینان از طراحی سازه خواهد شد. تخریب پیش رونده معمولا در سازه به دلیل از بین رفتن یکی از عضوهای اصلی سازه که معمولا ستون مورد نظر می باشد صورت می گیرد. با حذف ناگهانی یک ستون در سازه، در گره ای که ستون از سازه حذف شده است، تغییر مکانی که ماهیت لرزه ای دارد به وجود می آید. در این پژوهش تاثیر به کارگیری دستک های فلزی در دهانه ها با جانمایی مختلف در قاب خمشی بتنی در خرابی پیش رونده مورد بررسی قرار می گیرد. هدف از این ارزیابی این بوده که در مرحله اول میزان آسیب‌پذیری سازه‌های بتنی قاب خمشی تقویت شده با دستک در خرابی پیشرونده و همچنین تأثیر دستک در دهانه‌ها و ارتفاع سازه مورد مطالعه، محل عضو حذف‌شده (کناری یا میانی) و شماره طبقه‌ای که عضو در آن حذف‌شده، در برابر پدیده خرابی پیش‌رونده بررسی شود. نکته قابل‌ توجه در حالت‌های مختلف حذف اجزا، در تغییرات گسترده تلاش‌ها و تغییر مکان‌های گرهی و عدم تشکیل مفاصل پلاستیک در اعضا می‌باشد که می‌توان دلیل آن را به این صورت بیان کرد که با توزیع و جا نمایی مناسب دستک ها در دهانه‌ها و ارتفاع سازه، در محل حذف اعضا در این مدل، المان‌های سازه‌ای بیشتری وجود داشته و این موضوع موجب تقویت کنش زنجیره‌ای اعضا جهت حمل و انتقال بار و همچنین تثبیت فوری وضعیت به وجود آمده می‌گردد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation of nonlinear behavior of reinforced concrete moment frames retrofitted with steel haunch bracing under progressive collapse

نویسندگان [English]

  • Hossein Parvini Sani
  • Mojgan Taheri
Department of Civil Engineering, Zanjan Branch, Islamic Azad University, Zanjan, Iran
چکیده [English]

Progressive collapse is a nonlinear phenomenon that starts from the damage of a part of the structure and ends with the whole structure and its total damage. Therefore, the study of this phenomenon in high-rise and important structures while securing it will ensure the design process of the structure. Progressive collapse usually occurs in the structure due to the loss of one of the main members of the structure, which is usually the desired column. With the sudden removal of a column in the structure, in the node where the column is removed from the structure, there is a displacement that has a seismic nature. In this research, the effect of using steel haunch bracing with different locations in concrete moment frames is investigated under progressive collapse. The purpose of this evaluation was to determine the vulnerability of concrete structures retrofitted with steel haunch bracing as well as the effect of steel haunch bracing in spans and height of the structure, the place of eliminated element (edge or middle) and the number of the story in which the member was removed in the progressive collapse, is studied. A noteworthy point in different cases of component removal is in the wide changes of stresses and change of node displacement and lack of formation of plastic hinges in the members, which can be explained by the proper distribution and placement of steel haunch bracing in spans and height of the structure in the place of elimination of members in the model, there are more structural elements and this issue strengthens the catenary action of the members to transport and transfer load and also the immediate stabilization of the situation.

کلیدواژه‌ها [English]

  • Nonlinear behavior
  • Progressive collapse
  • Steel haunch bracing
  • Reinforced concrete moment frames
  • Retrofitting
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