مقایسه آزمایشگاهی و عددی رفتار ستون های بتن آرمه بیضی شکل ساخته شده از بتن های معمولی و پرمقاومت با و بدون غلاف و دورپیچ تحت بار محوری

نوع مقاله : علمی - پژوهشی

نویسندگان

1 دانشیار گروه عمران، واحد اهواز، دانشگاه آزاد اسلامی، اهواز، ایران

2 دانشجوی دکتری عمران- سازه، گروه عمران، دانشگاه آزاد اسلامی، واحد اهواز، اهواز، ایران

چکیده

در این تحقیق به مقایسه نتایج آزمایشگاهی و عددی رفتار ستون‌های بتن‌آرمه با مقطع بیضی‌ ساخته‌شده از بتن‌های معمولی و پرمقاومت که توسط غلاف پلاستیکی تقویت‌شده با الیاف شیشه و دورپیچ الیاف پلیمری تقویتی کربن ، محصور شدند، پرداخته شد. منظور از رفتار، ظرفیت فشاری و شکل‌پذیری ستون‌ها است. تأثیر نوع بتن، غلاف، دورپیچ و تعداد لایه‌های آن بررسی شدند. 12 ستون به قطرهای 200 و120 و ارتفاع 600 میلی‌متر ساخته شدند. ستون‌ها به دو گروه شش تایی از بتن‌های معمولی و پرمقاومت، و هر گروه نیز به دو بخش سه تایی تقسیم شدند؛ بخش اول دارای غلاف و بخش دوم فاقد غلاف بودند. از هر بخش یک ستون فاقد دورپیچ، یک ستون یک لایه و ستون دیگر دو لایه داشتند. مدل‌سازی عددی با نرم‌افزار آباکوس انجام گردید و نتایج حاصله با نتایج آزمایشگاهی مقایسه شدند که تطابق خوبی بین آن‌ها به‌دست آمد. نتایج تحقیق نشان داد که دورپیچ و غلاف باعث بهبود رفتار ستون‌ها گردیدند. افزودن یک لایه و دو لایه دورپیچ به‌ طور میانگین در روش آزمایشگاهی سبب افزایش %7/19 و %7/28 در ظرفیت فشاری در گروه اول و %11و %7/28 در گروه دوم و در روش عددی سبب افزایش %9/19 و %6/36 در ظرفیت فشاری در گروه اول و % 8/16و %9/30 در گروه دوم گردید؛ کاربرد غلاف میانگین افزایش ظرفیت ستون‌ها در روش آزمایشگاهی در گروه اول به میزان 15/4 برابر و در گروه دوم 51/3 برابر و در روش عددی در گروه اول به‌ میزان 26/4 برابر و در گروه دوم 25/3 برابر را نتیجه داد. هرچند که دورپیچ و غلاف هر دو محصوریت ایجاد می‌کنند، اما مقایسه اثر محصوریت غلاف با دورپیچ ‌نشان داد که غلاف به خاطر محصوریت بیشتر، تاثیر بسیار زیادتری بر بهبود رفتار ستون‌ها به‌ویژه ستون های ساخته شده از بتن معمولی دارد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Experimental and numerical comparison of the behavior of elliptic RCC’s made of NC and HSC, with and without casing and wrapping, under axial load

نویسندگان [English]

  • Seyed Fathollah Sajedi 1
  • Mohamad Morad Raghpour 2
1 Associate Professor, Department of Civil Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
2 PhD student, Department of Civil Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
چکیده [English]

In this study, the numerical and experimental results of the behaviour of RCC’s with an elliptic cross- section made of NC and HSC enclosed by a GRP casing and a CFRP wrapping were compared. Behaviour refers to the compressive capacity and ductility of columns. The effect of concrete type, casing, wrapping and layers number, were investigated. 12 columns with 200*120 diameter and 600 mm height were made. The columns were divided into two groups from NC and HSC, and each group was divided into two part of three; the first part had a casing and the second without casing. Each part had a column without wrapping, 2nd with one layer, and 3rd column with two layers. Numerical modelling was performed with ABAQUS software and the results were compared with experimental results, which were well matched. The results showed that the wrapping and casing improved the behaviour of the columns. Addition of one layer and two layers of wrapping on average in the experimental method causes an increase of 19.7% and 28.7% in the CC in the 1st group and 11% and 28.7% in the 2nd group and in the numerical method causes an increase of 19.9% and 36.6% in CC in the 1st group and 16.8% and 30.9% in the 2nd group. Averagely, the use of casing increased the capacity in the experimental method by 4.15 times in the 1st group and 3.51 times in the 2nd group; in the numerical method; this increase in the capacity in the 1st group was 4.26 times and in the 2nd group was 3.25 times. Although the casing and the wrapping both create confinement, comparison showed that the casing, due to its greater confinement, has a much greater effect on improving the behaviour of columns, especially columns made of NC.

کلیدواژه‌ها [English]

  • Elliptic reinforced concrete column
  • Behavior
  • High strength concrete (HSC)
  • GRP casing
  • CFRP wrapping
  • Abacus
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