بررسی کمانش موضعی ورق‌های فولادی در ستون‌هایCFT مستطیلی دارای میل مهار تحت فشار محوری

نوع مقاله : علمی - پژوهشی

نویسندگان

1 استادیار، دانشکده فنی و مهندسی، دانشگاه یاسوج، یاسوج، ایران

2 دانشکده فنی و مهندسی، دانشگاه یاسوج

3 دانشیار دانشگاه یاسوج

چکیده

در ستون‌های ‌فولادی پر شده با بتن ( CFT) دارای میل‌مهار، میل‌مهار‌های افقی که در طول ورق‌های فولادی قرار گرفته‌اند، برای تقویت اثر محصور شدگی هسته بتنی و به تاخیر انداختن کمانش استفاده می‌شوند. بنابراین، آنها مقاومت بالاتر، سختی بیشتر، انعطاف پذیری بهتر و جذب انرژی بیشتر در مقایسه با ستون‌های CFT معمولی دارند. در این مقاله، کمانش یک‌طرفه ورق‌های فولادی در ستون‌های CFT با میل‌مهار تحت بار محوری فشاری به روش ریلی‌ریتز با استفاده از توابع شکل یک ورق مستطیل شکل با شرایط مرزی مناسب بررسی شده است. لبه‌هایی از ورق فولادی که بارگذاری نشده‌اند، دربرابر چرخش به صورت الاستیک مقاومت می‌کنند. توابع مثلثاتی که شرایط مرزی ورق مستطیلی را برآورده می‌کند برای تعریف توابع شکل قابل قبول استفاده می‌شوند. بتن پرکننده به عنوان فونداسیون با سختی الاستیک زیاد در فشار و بدون سختی کششی مدل می‌شود، به گونه ای که کمانش فقط در یک جهت اتفاق می‌ افتد. از روش ضرائب لاگرانژ برای مدل‌سازی میل‌مهار‌‍‌ها استفاده شده است. برای تحلیل مسائل، برنامه‌نویسی در فضا‌ی متلب انجام شده است.این فرآیند برای بدست آوردن بار کمانش موضعی الاستو پلاستیک یک‌طرفه ورق فولادی با تعداد میل‌مهارهای مختلف استفاده شده است. مطابقت خوب نتایج عددی و آزمایشگاهی، صحت و کارایی روش را تأیید می‌کند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Local Buckling of Rectangular Concrete-Filled Steel Tubular (CFT) Columns with Binding Bars Subjected to Axial Compression Using the Rayleigh-Ritz Method.

نویسندگان [English]

  • Shamsedin Hashemi 1
  • Ali Akbar Khalili Baseri 2
  • Shahab Hatami 3
1 Assistant Professor, Department of Engineering, Yasouj University, Yasouj, Iran
2 Department of Engineering, Yasouj University
3 Department of Engineering, Yasouj University
چکیده [English]

In Concrete-Filled Steel Tubular (CFT) Columns with binding bars, horizontal binding bars arranged along the steel tubes are used to enhance the confinement effects on the core concrete and to postpone the initiation of local buckling. So, they have higher strength, more stiffness, better ductility and larger energy absorption compared to conventional CFT columns. In this paper, the unilateral buckling of steel plates in CFT Columns with binding bars under axial compression is investigated by the Rayleigh-Ritz method, using the shape functions of a rectangular plate with appropriate boundary conditions. It is assumed that the unloaded edges of the steel plate are elastically restrained against rotation. Trigonometrical functions that satisfy the boundary conditions of the rectangular plate are used to define the shape functions. In unilateral buckling, the folled concrete is described as an elastic foundation with high stiffness in compression and without tensile stiffness, such that buckling occurs in only one direction. The Lagrange multiplier technique is used to model the binding bars. The solution algorithms of the problems are written in MATLAB code. The solution of this process is used to obtain the elasto-plastic local buckling load of unilaterally-restrained steel plate with various numbers of binding bolts depends on spacing between them. Finally, the numerical results were compared with experiment results. The excellent agreements of the results verify the accuracy and efficiency of the method.

کلیدواژه‌ها [English]

  • Concrete-Filled Steel Tubular(CFT) Columns
  • steel plate
  • binding bar
  • Rayleigh-Ritz method
  • unilateral buckling
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