مدل‌سازی و ارزیابی روش‌های طراحی تیرهای عمیق بتن مسلح

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار گروه مهندسی عمران، دانشگاه آزاد، واحد قم، قم، ایران

2 مهندسی عمران، دانشکده عمران و معماری، موسسه ی پویش، قم، ایران.

چکیده

تیرهای عمیق به تیرهایی گفته می‌شود که در مقایسه با تیرهای معمولی،‌ دارای نسبت زیاد ارتفاع به دهانه باشند. در تیرهای عمیق به دلیل داشتن هندسه‌ی خاص توزیع کرنش در مقطع به صورت خطی نیست و عموماً دارای رفتاری برشی هستند. بر همین اساس این تیرها به روش متفاوتی نسبت به تیرهای معمولی طراحی می‌شوند. طراحی تیرهای عمیق با توجه به کاربرد وسیع آن‌ها یک مسئله حیاتی در مهندسی سازه به‌حساب می‌آید. تا‌کنون مطالعات متعددی برای تعیین روابط یا روش‌هایی برای طراحی تیرهای عمیق صورت گرفته است. این مطالعات منجر به پیدایش روش‌های مختلف برای تحلیل و طراحی این تیرها شدند. با این حال آیین نامه بتن ایران بدون توجه به این روش ها مدت هاست از یک رابطه ساده و قدیمی استفاده می کند. در این پژوهش روش‌ها و روابط معتبر ارائه‌شده توسط دیگر محققان در کنار روش آیین نامه بتن ایران بررسی و ارزیابی شدند. مقایسه روش آیین نامه بتن ایران و بست‌وبند آیین‌نامه‌ی بتن آمریکا در طراحی تیرهای عمیق بتن مسلح نشان داد که نتایج روش بست‌وبند همبستگی بیشتری با نتایج آزمایشگاهی دارند. طراحی مطابق با روش بست‌وبند منجر به 27 درصد خطای کمتر یا به عبارتی دیگر 27 درصد صرفه‌جویی در مصرف مصالح نسبت به روش آیین‌نامه بتن ایران می شود. همچنین، در این پژوهش رابطه‌ی جدیدی برای پیش‌بینی نیروی برشی تیرهای عمیق بتن مسلح بر اساس 240 نمونه‌ی آزمایشگاهی با استفاده از روش رابطه‌سازی ژنتیک ارائه شد. رابطه ی پیشنهادی توانست با میانگین خطای 6% نتایج آزمایشگاهی را پیش بینی کند.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Modeling and Evaluation of Design Methods of Reinforced Concrete Deep Beams

نویسندگان [English]

  • Mahdi Moradi 1
  • Sayed Mohammad Bagher Saraf Zadeh 2
1 Assistant Professor, Department of Civil Engineering, Qom Branch, Islamic Azad University, Qom, Iran.
2 Department of Civil Engineering, School of Civil Engineering and Architecture, Pooyesh Institute, Qom, Iran
چکیده [English]

Deep beam have large depth/thickness ratio compared to conventional beams. In deep beams, the bending strain distribution through the depth of transverse sections of beam considerably deviates from the linear distribution. So their behavior is different with ordinary beams and are designed based on shear strength. The design of deep beams, due to their widespread use, is a crucial issue in structural engineering. So far, numerous studies have been done to determine the shear strength relations or models for deep beams. One widely used approach to determine shear strength of is the strut-and-tie method, which is employed by the American Concrete Association (ACI). However, It has been a long time since the Iranian Concrete Code (ICC), regardless of this research, uses a direct relation for the design of deep beams. In this research, methods and relations provided by other researchers along with the ICC method for deep beam design have been evaluated based on 240 experimental specimens. Moreover, a new equation for predicting the shear strength of RC deep beams using the genetic programming (GP) method is presented. Some input and output data should be used for feeding GP and equations producing. This equation was only based on primary specifications of RC deep beams and compared with other methods presented in the literature. In addition, the effect of different parameters on shear strength of RC deep beams were investigated. The results of this study showed that the proposed equation had acceptable accuracy compared to the experimental results and other equations presented in the literature. The proposed equation predicts the experimental results with an average error of 6%. Comparison of the results of the of ICC method in the design of deep beams with ACI method results showed that design in accordance with the ACI method resulted in a 27% lower error.
 

کلیدواژه‌ها [English]

  • Reinforced concrete
  • Deep beam
  • Genetic programming
  • Shear strength

مراجع

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سابقه مقاله

  • تاریخ دریافت: 24 آذر 1398
  • تاریخ بازنگری: 03 اردیبهشت 1399
  • تاریخ پذیرش: 08 اردیبهشت 1399

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