ارزیابی رفتار لرزه‌ای قاب‌های فولادی مقید شده با مهاربندهای کمانش تاب هسته مرکب

نوع مقاله : مقاله پژوهشی

نویسندگان

گروه مهندسی عمران، دانشگاه کاشان، کاشان، ایران

چکیده

قاب مهاربندی کمانش تاب نوع ویژهای از قابهای فولادی مهاربندی هم‌محور است که در آن مهاربندها در برابر فشار کمانش نمی‌کنند و در نتیجه اتالف انرژی مطلوبی از خود نشان می‌دهد. لیکن هنگام وقوع زلزله‌های بزرگ، سختی پایین این مهاربندها بعد از تسلیم سبب تغییرمکان‌های دائمی بزرگ در قاب می‌شود. هدف تحقیق حاضر، ارزیابی رفتار لرزهای یک سیستم نوین سازهای موسوم به قاب فولادی مقید شده با مهاربندهای کمانش تاب هسته مرکب و مقایسه آن با رفتار قاب مهاربندی کمانش تاب متداول می‌باشد. بدین منظور، از سه روش تحلیل استاتیکی غیرخطی، تحلیل تاریخچه زمانی غیرخطی و تحلیل دینامیکی افزایشی روی انواع مدل‌های قاب مهاربندی کمانش تاب متداول و مرکب دارای طبقات مختلف استفاده می‌شود. مقادیر متوسط ضریب رفتار در قاب‌های فولادی مقید شده با مهاربند کمانش تاب مرکب برای روش‌‌های طراحی حالت حد نهایی و تنش مجاز به ترتیب برابر 10/2 و 14/7 به دست می‌آید. برای انجام تحلیل‌های تاریخچه زمانی، هفت زوج شتاب نگاشت از زلزله‌های گذشته در سطوح خطر مختلف مورد استفاده قرار می‌گیرد. نتایج تحلیل‌ها حاکی از این است که قاب‌های فولادی مرکب از بهبود عملکرد قابل توجهی در ضریب رفتار و نیز کاهش چشمگیر در مقدار جابه‌جایی پسماند بام نسبت به قاب‌های مهاربندی کمانش تاب متداول برخوردار هستند. به عالوه، با توجه به ارتفاع قاب و شدت زلزله، تغییر مکان جانبی نسبی درون طبقه در قاب‌های مرکب می‌تواند کاهش قابل ملاحظه‌ای داشته باشد

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Evaluation of Seismic Behavior of Steel Frames Constrained with Hybrid Core Buckling-restrained Braces

نویسندگان [English]

  • Mehdi Alborzi Verki
  • Hossein Tahghighi
Civil engineering department, University of Kashan, Kashan, Iran
چکیده [English]

Bucking restrained braced frame (BRBF) is a special type of concentrically braced frames that the braces do not buckle in compression. As a result, it shows a desirable energy dissipation behavior. However, low post-yield stiffness of these braces causes large residual deformations at high levels of earthquake intensities. The aim of this article was evaluation of the seismic behavior of a new steel structural system known as hybrid buckling-restrained braced frame (HBRBF). Nonlinear static analysis, nonlinear time history analysis and nonlinear incremental dynamic analysis (IDA) methods were used for standard and hybrid core BRBFs with different stories. The average values of seismic behavior factor (R) for HBRBFs were obtained 10.2 and 14.7 for ultimate limit state and allowable stress design methods, respectively. In order to carry out response history analyses, past earthquakes records were used with different hazard levels. Hybrid buckling-restrained braced frames were shown to have a significant improvement over standard BRBFs in terms of behavior factor and damage measures including inter-story drift ratios and residual displacements.

کلیدواژه‌ها [English]

  • Hybrid Buckling-restrained Brace
  • Behavior Factor
  • Residual Displacement
  • Nonlinear Analysis
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