مطالعه پارامتری پاسخ عرضی ساختمان های بلند در برابر باد بر مبنای تحلیل حوزه فرکانس و ارتعاشات تصادفی

نوع مقاله : علمی - پژوهشی

نویسنده

استادیار، مهندسی سازه، دانشگاه آزاد اسلامی، واحد خورموج، خورموج، ایران

چکیده

با افزایش روزافزون ارتفاع و لاغری ساختمان های بلند، پاسخ دینامیکی در مقابل باد به‎ویژه پاسخ عرضی از عوامل تعیین‎کننده در معیار آسایش ساکنین ساختمان های بلند محسوب می شود. در این تحقیق، پاسخ‎ عرضی ساختمان های بلند در برابر باد به صورت پارامتری، با استفاده از تحلیل حوزه فرکانس سیستم های چند درجه آزادی و مبانی ارتعاشات تصادفی مورد تحلیل و بررسی قرار گرفته است. سازه بلند به صورت تیر طره ای قائم با جرم‎های متمرکز در گره ها مدل سازی گردیده است. کلیه مراحل مدل سازی و تحلیل سازه، شامل المان بندی، تعیین ماتریس انتقال سازه، استخراج ماتریس های تابع طیفی نیروهای عرضی باد و انتگرال گیری عددی برای محاسبه انحراف معیار جابجایی و شتاب عرضی، با برنامه نویسی در محیط نرم افزار متلب انجام شده است. تاثیر پارامترهای مختلف از قبیل سرعت مبنای باد، لاغری سازه، نسبت طول به عرض در پلان برای ساختمان های با مقطع مستطیل و نسبت بعد فوقانی به تحتانی برای ساختمان های مقطع متغیر، مورد تحلیل و بحث قرار گرفته است. از نتایج حاصله می توان به نقش مهم نسبت لاغری در پاسخ عرضی سازه اشاره نمود. برای ساختمان های با مقطع متغیر در ارتفاع، با کاهش نسبت عرض فوقانی به عرض تحتانی، جابجایی عرضی تراز فوقانی به‎طور قابل ملاحظه ای کاهش می یابد. همچنین مطابق نتایج، شتاب عرضی ساختمان های مطالعه شده فراتر از حد آسایش ساکنین بودکه نیاز به تمهیدات کنترل ارتعاشات می باشد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Parametric Study of the Crosswind Response of Tall Buildings Using Frequency Domain Analysis and Random Vibration Method

نویسنده [English]

  • Nahmat Khodaie
Department of Civil Engineering, Islamic Azad University, Khormoj branch, Khormoj, Iran
چکیده [English]

By increasing the height and slenderness of tall buildings, the wind-induced dynamic response especially crosswind response becomes the governing parameter in the occupant comfort requirement of tall buildings. In the present study, crosswind response of tall buildings has been investigated using the frequency domain analysis of multi-degrees-of-freedom systems based on the random vibration method. The tall structure has been modeled as a vertical cantilever beam with the masses lumped at the nodes. All the modeling and analysis procedure, including element meshing, determining the transfer matrix, calculating the matrix of crosswind force spectrum, and the numerical integration to obtain the root-mean-square (RMS) displacement and acceleration responses are carried out using MATLAB software. The effect of different parameters, such as basic wind speed, aspect ratio, side ratio for rectangle section and top to bottom width ratio for tapered tall buildings has been investigated. The results show that the slenderness ratio has an important role on the across-wind response. For tapered buildings, the crosswind displacement response decreases considerably with increasing the top to bottom width ratio.  For the studied tall buildings, the crosswind acceleration response is higher than the occupant comfort level and it requires to be reduced using an appropriate control strategy.

کلیدواژه‌ها [English]

  • Crosswind response
  • Tall building
  • Frequency domain analysis
  • Random vibration
  • Parametric study
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