نوع مقاله: مقاله پژوهشی

نویسندگان

1 استادیار، عضو هیأت علمی گروه عمران دانشگاه قم، ایران

2 دانشجوی دکتری رشته مهندسی عمران گرایش سازه، دانشگاه قم، ایران،

10.30478/jcsm.2019.156219.1099

چکیده

 
توانایی هسته بتن یک ستون بتن مسلح جهت مقاومت در برابر کرنش­های فشاری با فشار ناشی از محصورشدگی افزایش می­یابد. به منظور تضمین ظرفیت تغییر شکل جانبی مناسب ستون­های بتن آرمه بایستی میلگردهای محصورکننده را با توجه به بار محوری افزایش داد. از طرفی مقاومت و انعطاف­پذیری هر ستون­ بتن مسلح از طریق بهبود محصورشدگی مناطق لولای پلاستیک ارتقاء می­یابد. این بهبود تضمین پایداری لرزه­ای سازه در طول یک زلزله است. یکی از مهمترین ویژگی­های سازه­های بتنی در مقابل نیروهای ناشی از زلزله رفتار شکل­پذیر آنها است. یافتن مقادیری برای معیار شکل­پذیری به دلیل پیچیدگی­های رفتار سازه­ها و مشخص نبودن صریح همه عوامل موثر بر آن، با مشکلات زیادی همراه است. آئین­نامه­های مختلف نیز معیارهای متفاوتی برای شکل­پذیری بیان می­کنند. هدف از پژوهش حاضر ارائه یک معیار محصورشدگی بر مبنای نیاز شکل­پذیری است. در این مقاله ضمن بررسی آئین­نامه­های مختلف، روابطی برای طراحی آرماتورهای عرضی محصورکننده دو نوع ستون­ با مقطع دایره­ای و مستطیلی در حالت شکل­پذیری زیاد و متوسط استخراج شده است. جهت صحت­سنجی روابط، مقادیر آرماتور طراحی ستون­های بتن آرمه با مقادیر به دست آمده از روابط مقررات ملی مورد ارزیابی قرار گرفتند. نتایج استفاده از روابط پیشنهادی نشان می­دهد که مقادیر آرماتورهای طراحی مقاطع مورد بررسی در هر دو حالت، شکل­پذیری کاهش یافته را در بر دارد

کلیدواژه‌ها

عنوان مقاله [English]

Investigation of analytical relations on the effect of confinement in the design of reinforced concrete columns

نویسندگان [English]

  • Ehsan Dehghani 1
  • Mohammad Hossein Taghavi Parsa 2

1 Assistant Professor, Faculty Member of Department of Civil Engineering, University of Qom, Iran.

2 Ph.D. student of Civil Engineering, Structural Engineering, University of Qom, Iran.

چکیده [English]

 
Concrete core capability of a reinforced concrete columns to withstand compressive strain caused by the confinement pressure increases. In order to ensure proper lateral deformation capacity of reinforced concrete columns enclosing the bars should be increased according to the axial load. On the other hand, the strength and flexibility of each reinforced concrete is enhanced by improving the enclosure of plastic hinge areas. This ensures improved seismic stability during an earthquake. One of the most important characteristics of concrete structures against the forces of earthquake is their ductile behavior. Finding the values for standard plasticity due to the complexity of the structural behavior and the lack of explicit all its influencing factors, is associated with many problems. Also various regulations are expressing the different criteria for ductility. The purpose of the present study is to provide a confinement criterion based on the need for ductility. In this article, we review the various regulations, is extracted relations for design of enclosed transverse reinforcement of two type of columns, with circular and rectangular sections, In the case of medium and high ductility. In order to verify the relations, reinforcement values for designing reinforced concrete columns evaluated with the values obtained from Iranian national regulations relations. The results of the proposed relations show that the values of the design reinforcement of sections for both levels of ductility is reduced .
 

کلیدواژه‌ها [English]

  • Design of confining transverse reinforcement
  • concrete reinforcement columns
  • ductility surfaces
  • plastic hinge length
  • curvature ductility factor

 

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