اثر بتن خودتراکم بر رفتار اتصالات خارجی تیر- ستون بتنی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار دانشکده مهندسی دانشگاه آزاد اسلامی واحد مشهد

2 استاد دانشکده مهندسی دانشگاه فردوسی مشهد

چکیده

در این پژوهش، رفتار اتصالات خارجی بتنی ساخته شده از بتن معمولی (NC) و خودتراکم (SCC) مورد بررسی قرار گرفته است. عامل­های مورد بررسی شامل نوع خم میلگردهای طولی تیر، میلگردهای عرضی هستۀ اتصال و نوع بتن مصرفی هستند. مطالعه رفتار اتصال تحت اثر عامل­های مورد نظر در دو بخش آزمایشگاهی و تحلیلی بررسی شده است. در بخش آزمایشگاهی، تعداد 10 نمونه اتصال خارجی بتنی با مقیاس 2/1 ساخته شده و تحت اثر نیروی محوری ثابت در ستون  و بارگذاری رفت و برگشتی در تیر آزمایش شده است. در بخش تحلیلی، نمونه­های مورد نظر با استفاده از نرم­افزار ABAQUS مدل سازی و تحلیل شده اند. ظرفیت­های به دست آمده از روش تحلیلی برابری خوبی با نتایج آزمایشگاهی دارند. نتایج تحقیق نشان می­دهد که استفاده از بتن خودتراکم علاوه بر سهولت در اجرا، موجب افزایش کارایی و شکل پذیری اتصال و افزایش چسبندگی بتن با میلگرد می­شود. برای استفاده از کارایی بتن خودتراکم، اجرای آن در تمام اتصال ضروری نیست و می­توان از آن فقط در ستون یا در محدوده هسته استفاده نمود. از طرف دیگر، افزایش مقاومت بتن در صورت ثابت بودن درصد آرماتور مقطع می­تواند موجب تغییر سازوکار شکست اتصال از حالت برشی در هسته به حالت خمشی در تیر شود. 

کلیدواژه‌ها

عنوان مقاله [English]

Effect of Self-Consolidating Concrete on Beam-Column Exterior Joints

نویسندگان [English]

  • Hamid Shirazi 1
  • Mohammad Reza Esfahani 2
1 iAssistant Professor, Ferdowsi University of Mashhad and, iiAzad University, Mashhad Branch, Mashhad, Iran
2 Professor, Ferdowsi University of Mashhad, Mashhad, Iran
چکیده [English]

In this research, behavior of exterior concrete beam-column joints made of normal concrete (NC) and self-consolidating concrete (SCC) is investigated. The variables include the type of beam longitudinal bar anchorage in joint, transverse reinforcement of joint and strength of concrete. Experimental and analytical investigation of joint behavior is carried out. In the experimental part, 10 semi-scale exterior beam-column joints were manufactured and subjected to a constant column axial load and beam quasi-static cyclic load. In the analytical part, the ABAQUS software is used for modeling and analyzing of test specimens. Based on the results, the experimental and analytical joint capacities are in good agreement. Results show that using self-consolidating concrete in joints, apart from easier concrete placement, can increase the workability and ductility of connection and result in a better bond with reinforcing bars. Also, by increasing the concrete strength, the failure mechanism of a connection may change from shear failure in joint to flexural failure in beam.

کلیدواژه‌ها [English]

  • Exterior Concrete Beam-Column Joints
  • Finite Elements
  • self-consolidating concrete
  • Hysteresis Diagram

مراجع

[1] Scott, R. H., “The effects of Detailing on RC Beam-Column Connection Behaviour”, The Structural Engineer, V. 70, No. 18, pp. 318-324, 1992. 1
[2]Abdel-Fattah, B., and Wight, J.K., “Study of Moving Beam Plastic Hinging Zones for Earthquake-Resistant Design of R/C Buildings”, ACI Structural Journal, Vol. 84, No. 1, pp. 31-39, 1987. 2
[3]Wallace, J. W., McConnell, S. W., Gupta, P. and Cote, P. A., “Use of Headed Reinforcement in Beam-Column Joints Subjected to Earthquake Loads", ACI structural Journal, Vol. 95, No. 5, pp. 590-606, 1998. 3
[4]Kang, T.H.K., Sang, S.H., and Choi, D.U., “Bar Pullout Tests and Seismic Tests of Small-Headed Bars in Beam-Column Joints”, ACI structural Journal, Vol. 107, No. 1, pp. 32-42, 2010. 4
[5]Henager, C.H., “Steel Fibrous, Ductile Concrete Joint for Seismic-Resistant Structures”, Reinforced Concrete Structures in Seismic Zones, SP 53-14, American Concrete Institue, Detroit, pp. 371-386, 1974. 5
[6]Bertero, V.V., Popov, E.P., and Frzani, B., “Seismic Behaviour of Lightweight Concrete Beam-Column Subassemblages”, ACI Structural Journal, Vol. 77, No. 7, pp. 44-52, 1980. 6
[7]Lin, C. H.; Lin, S.P.; and Tseng,C. H.,”High-Workability Concrete Columns under Concentric Compresion”, ACI Structural Journal, V.101, No. 1, Jan.-Feb. pp. 85-93, 2004. 7
[8]Lin, C. H. and Lin, S.P. ,”Flexural Behavior of High-Workability Concrete Columns under Cyclic Loading”, ACI Structural Journal, V.102, No. 3, May-June pp. 412-421, 2005. 8
[9]Chan,y.W.; Chen, y. S.; and Liu, y. S., “Development of Bond Strength of Reinforcement Steel in Self-Consolidating Concrete”, ACI Structural Journal, V.100, No. 4, July-Aug., pp. 490-498, 2003. 9
[10]Paultre, P.; Khayat, K. H.; Cusson, D.; and Tremblay, S., “Structural Performance of Self-Consolidating Concrete Used in Confined Concrete Column”, ACI Structural Journal, V.102, No. 4, July-Aug., pp. 560-568, 2005.
[11]Esfahani M. R., Lachemi M., and Kianoush M. R., “Top-Bar Effect of Steel Bars in Self-Consolidating Concrete (SCC)”, Engineering Structures Journal, Elsevier Sci Ltd, Oxford, England, No. 30, pp.52-60, 2008.
[12]Chen, y. F., “An Investigation on Confinement Behavior of Square Self-CoMPacting Concrete Columns”, MS thesis, Department of Civil Engineering, National Taiwan University, Taiwan, 245 p p, 2003. 12
[13]ACI Committee 209, “Prediction of Creep, Shrinkage and Temperature Effects in Concrete Structures”, Designing for Creep and Shrinkage in Concrete Structures, SP-76, American Concrete Institue, Farmington Hills, MI, pp. 93-300, 2008. 13
[14]Chien, H., L., and Chao, L., H., and Shin, P., L., and Chin, H., L., “Self-Cosolidating Concrete Columns under Cocentric Compression”, ACI Structural Journal, V.105, No. 4, July-Aug., pp. 425-432, 2008. 14
[15]ACI Committee 318, “Building Code Requirements for Structural Concrete(ACI 318-11) and Commentary (318R-11)”, American Concrete Institue, Farmington Hills, Mich, 443pp, 2011. 15
[16]ACI Committee 374, “Acceptance criteria for Moment Frames Based on Structural Testing and Commentary(ACI 374.1-05)”, American Concrete Institue, Farmington Hills, MI, 9pp, 2005. 16
[17]Ehsani, M. R., and Alameddine, F., “Design Recommendations for Type 2 High-Strenth Reinforced Concrete Connections”, ACI Structural Journal, Vol. 88, No. 3, pp. 277-291, 1991. 17
[18]Lubliner, J., J. Oliver, S. Oller, and E. Onate, “A Plastic- Damage Model for Concrete”, International Journal of Solids and Structures, vol. 25, pp. 299-329, 1989. 18
[19]Lee, J., and G. L. Fenves, “Plastic- Damage Model for Cyclic Loading of Concrete Structures”, Journal of Engineering Mechanics, vol. 124, no.8, pp. 892-900, 1998. 19
[20]Thorenfeldt, E., and Tromaszwicz, A., “Mechanical Properties of High-Strength Concrete and Application in Design”, Proceedings of The Symposium Utilization of High-Strength Concrete, Tapir, Trondheim, pp. 149-159, 1987. 20
[21]Collins, MP., and Porasz, A., “Shear Design for High-Strength Concrete”, CEB Bulletined, Information, No. 193, pp. 77-83, 1989. 21
[22]Collins, MP., and Mitchell, D., “Prestressed Concrete Structure”, Prentice- Hall Inc; Englewood Cliffs, New Jersey, pp. 766, 1991. 22
[23]Li, B., and Tran, T.N., “Seismic Behaviour of Reinforced Concrete Beam-Column Joints with Vertically Distributed Reinforcement”, ACI structural Journal, Vol. 106, No. 6, pp. 790-799, 2009.

فایل ها

هم رسانی

ارجاع به این مقاله

آمار