نقش میراگر لزج بر بهبود رفتار و کاهش ضربه ساختمانها تحت ورودی لرزه ای تصادفی

نوع مقاله : علمی - پژوهشی

نویسندگان

1 دانشگاه صنعتی نوشیروانی بابل، بابل، ایران

2 دانشیار، دانشکده مهندسی عمران، دانشگاه صنعتی نوشیروانی بابل، بابل، ایران

3 استاد، دانشگاه صنعتی نوشیروانی بابل، بابل، ایران

چکیده

میراگرهای لزج، به عنوان حالت خاصی از میراگرهای غیرفعال، ابزاری سودمند جهت کاهش پاسخ لرزه ای سازه ها و جلوگیری از برخورد آنها در زمان زلزله می باشند که البته می توان جانمایی های مختلفی، شامل بین دو ساختمان و یا درون آنها و نیز در تراز طبقات مختلف، را برای چنین میراگرهایی لحاظ نمود. مقاله حاضر به بررسی حالتهای مختلف از این جانمایی ها می پردازد. بدین منظور ابتدا دو سیستم یک درجه آزادی متصل شده با میراگر لزج مدنظر قرار گرفته و مشخصات دینامیکی مجموعه بررسی می گردد. سپس پاسخ تغییرمکان نسبی بین دو سازه یک درجه آزاد متصل شده با پاسخ نظیر حاصل از اضافه نمودن مستقیم میراگر به سازه ها تحت ورودی بصورت طیف سفید ایده آل با یکدیگر مقایسه می گردد. همچنین پاسخ شتاب مطلق دو سازه یک درجه آزادی در دو حالت میراگر بین دو سازه و میراگر درون آنها تحت ورودی طیف فیلتر شده کانای تاجیمی با یکدیگر مقایسه می گردد. در ادامه، دو سیستم دو درجه آزاد در دو حالت متصل و آزاد و بازای جانمایی های مختلف میراگر بین دو سازه تحت ورودی طیف سفید قرار گرفته و مقایسه نسبی بین آنها صورت می گیرد. نتایج نشان می دهد که استفاده از میراگر بین دو سازه، ضمن حفظ کاهش تغییرمکان دو سازه و نیز کاهش شتاب مطلق مجموعه، تغییرمکان بین دو سازه کمتری را در نسبت های فرکانسی پایین بین دو سازه و در قیاس با میراگر درون ساختمان ها بدست خواهد داد. همچنین افزودن میراگر بین دو سازه در تراز طبقات بالاتر سبب کاهش بیشتر در حرکت نسبی دو سازه و نتیجتاً کاهش بیشتر احتمال وقوع برخورد در قیاس با حالتی می شود که میراگر بطور یکنواخت در طبقات توزیع شده باشد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

The rule of viscous damper for behavior improvement and pounding mitigation under random seismic input

نویسندگان [English]

  • Hamed Ahmadi Taleshian 1
  • Alireza Mirza Goltabar Roshan 2
  • Javad Vaseghi Amiri 3
1 Babol Noshirvani University of Technology, Babol, Iran
2 Associate Professor, Faculty of Civil Engineering, Noshirvani University of ‎Technology, Babol, Iran
3 Professor, Faculty of Civil Engineering, Babol Noshirvani University of technology, Babol, Iran
چکیده [English]

Viscous dampers, as a special type of passive dampers, are efficient tools for seismic improvement of the buildings and eliminating the effects of seismic pounding during earthquakes. Such dampers can be installed between the adjacent buildings or inside them and also at different story levels. This paper attempts to investigate the effects of different damper placements. Accordingly, two single degree of freedom systems connected by viscous dampers were considered first and the dynamic characteristics of the system have been determined. Then, relative displacements of the buildings are compared with damping inside building for one-story models and with free undamped response for two-story models, under ideal white noise seismic input. Absolute accelerations of the one-story buildings are also compared by assigning the Kanai-Tajimi filtered white noise as the input. Results reveal that using dampers between buildings is more suitable than using them inside buildings, as the relative displacement between adjacent buildings would be reduced for lower values of uncoupled frequency ratios of structures and the absolute acceleration would also be significantly reduced for both buildings, rather than just for one of them. Furthermore, use of dampers at the top level would be more beneficial than using them throughout the height of the systems for seismic pounding mitigation.

کلیدواژه‌ها [English]

  • Pounding mitigation
  • Viscous damper
  • White-Noise analysis
  • Seismic response
  • Dynamic Properties
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