بررسی تاثیر میلگردهای CFRP بر ظرفیت برش سوراخ کننده در دال های بتن مسلح تخت

نوع مقاله : علمی - پژوهشی

نویسندگان

1 دانشجوی مقطع کارشناسی ارشد مهندسی عمران-سازه، موسسه آموزش عالی رحمان، رامسر، ایران

2 استاد و عضو هیئت علمی گروه مهندسی عمران، دانشگاه گیلان، رشت، ایران

3 استادیار و عضو هیئت علمی گروه مهندسی عمران و معماری، موسسه آموزش عالی رحمان، رامسر، ایران

چکیده

هدف از پژوهش حاضر بررسی رفتار اتصالات ستون-دال بتن مسلح ‌تخت تحت برش سوراخ‌کننده می‌باشد. تعداد 49 نمونه‌ی اتصال ستون-دال بتن مسلح تخت با استفاده از نرم‌افزار اجزای محدود ABAQUS شبیه‌سازی شدند. تعداد 6 نمونه‌ اتصال ستون میانی، 5 نمونه‌ اتصال ستون لبه و 3 نمونه اتصال ستون گوشه به دال بتن مسلح تخت از میان پژوهش‌های آزمایشگاهی پیشینیان انتخاب شدند و جهت بررسی توانایی نرم‌افزار مذکور شبیه‌سازی شدند. نتایج شبیه‌سازی از نظر انطباق حالت گسیختگی، نحوه‌ی شروع و گسترش تر‌ک‌ها با نمونه‌ها‌ی آزمایشگاهی بسیار رضایت بخش بود به‌طوری‌که نسبت ظرفیت برش سوراخ‌کننده‌ی نتایج آزمایشگاهی به شبیه-سازی با نرم‌افزار ABAQUS برای اتصال با ستون میانی، ستون لبه و ستون گوشه به ترتیب در حدود 0.86 تا 0.92، 0.95 تا 0.95 و 0.91 تا 0.95بوده است. نسبت ظرفیت برش سوراخ‌کننده براساس آیین‌نامه‌های ACI 440.1R-15،CSA S806-12 ،JSCE-97 و BSI 8110-97 نیز ارائه شد. آیین‌نامه‌ی ACI 440.1R-15 بیشترین مقدار نسبت ظرفیت برش سوراخ‌کننده را داشت. این نسبت برای اتصالات با ستون میانی و ستون لبه به ترتیب در حدود2.91 تا 4.75 و 2.01 تا 2.99 بوده است. تعداد 23 نمونه به‌منظور بررسی رفتار اتصال تسلیح شده با میلگردهای CFRP به‌جای میلگردهای فولادی یا GFRP نیز شبیه‌سازی شدند. نتایج نشان داد که استفاده از میلگردهای CFRP به‌جای میلگردهای GFRP نقش به‌سزایی در افزایش ظرفیت برش سوراخ‌کننده‌ی نمونه‌های اتصال ستون-دال بتن مسلح تخت داشته است و علت آن ضریب ارتجاعی و مقاومت کششی بالاتر میلگردهای CFRP نسبت به میلگردهای GFRP می‌باشد. تعداد 6 نمونه نیز به‌منظور بررسی اثر افزایش ضخامت دال بتن مسلح تخت شبیه‌سازی شدند و نتایج نشان داد که با افزایش ضخامت دال تخت، ظرفیت برش سوراخ‌کننده افزایش 27.05 درصدی تا 49.50 درصدی خواهد داشت. لازم به ذکر است که با افزایش ابعاد ستون در قالب شبیه‌سازی تعداد 6 اتصال، ظرفیت برش سوراخ‌کننده‌ی نمونه‌ها در حدود 11.84 درصد تا 17.89درصد افزایش داشته است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation of the effect of CFRP bars on punching shear capacity in Reinforced Concrete (RC) flat slabs

نویسندگان [English]

  • Hoda Kouhnejhad 1
  • Rahmat Madandoust 2
  • Seyedeh Mahdieh Miralami 3
1 Master student of Structural Engineering, Department of Civil Engineering, Rahman Institute of Higher Education, Ramsar, Iran
2 Professor, Structural Engineering, Faculty of Engineering, University of Guilan, Rasht, Iran
3 Assistant Professor, Structural Engineering, Department of Civil Engineering, Rahman Institute of Higher Education, Ramsar, Iran
چکیده [English]

The present study deals with the punching shear capacity of reinforced concrete (RC) flat slabs reinforced with Fiber Reinforced Polymer (FRP) bars. A total of 49 reinforced concrete (RC) column-slab connections were simulated using ABAQUS finite element software. The numbers of six interior column-slab connections, five edge column-slab connections, and three corner column-slab connections were selected from the previous test results and were simulated to evaluate the software's ability. The simulation results were so satisfactory in terms of failure mode, initial and propagation of cracks that the tested to simulated punching shear capacity of interior and edge column-slab connections were about 0.86 to 0.92, 0.85 to 0.95, and 0.91 to 0.95 respectively. The punching shear capacity was predicted by ACI 440.1R-15, CSA S806-12, JSCE-97, and BSI 8110-97. The punching shear design equation based on ACI 440.1R-15 underestimated the punching shear capacity with 2.91 to 4.75 (Interior column-slab connections) and 2.01 to 2.99 (Edge column-slab connections), respectively. The numbers of 23 specimens were simulated to investigate the punching shear capacity of reinforced concrete (RC) flat slabs with carbon fiber-reinforced polymer (CFRP) reinforcing bars. The results showed that the replacement of CFRP bars instead of GFRP bars has played a significant role in increasing the punching shear capacity of reinforced concrete (RC) column-slab connections. To investigate the effect of increasing slab thickness, the numbers of six specimens were simulated. With increasing the thickness of the flat slab, the punching shear capacity will increase from 27.05% to 49.50%. It should be noted that with the increase of column dimensions in the form of simulation of six specimens, the punching shear capacity of the specimens has increased about 11.84% to 17.89%.

کلیدواژه‌ها [English]

  • Edge column- RC flat slab
  • Interior column-RC flat slab
  • Corner column-RC flat slab
  • Punching shear capacity
  • FRP bar
  • Simulation
  • Slab center displacement
[1] El-Gendy, M. G., El-Salakawy, E. (2018a). Punching shear behavior of GFRP-RC slab-column edge connections. Special Publication, 322, 1-5.
[2] El-Gendy, M. G., El-Salakawy, E. F. (2018b). Lateral displacement deformability of GFRP-RC slab-column edge connections. Special Publication, 327, 1-52.
[3] El-Gendy, M., El-Salakawy, E. (2019). Effect of flexural reinforcement type and ratio on the punching behavior of RC slab-column edge connections subjected to reversed-cyclic lateral loads. Engineering Structures, 200, 1-11.
[4] El-Gendy, M. G., El-Salakawy, E. F. (2020). GFRP shear reinforcement for slab-column edge connections subjected to reversed cyclic lateral load. Journal of Composites for Construction, 24(2), 1-14.
[5] El-Gendy, M. G., and El-Salakawy, E. F. (2020). Assessment of punching shear design models for FRP-RC slab–column connections. Journal of Composites for Construction, 24(5), 1-15.
[6] Hassan, M., Ahmed, E. A., and Benmokrane, B. (2013). Punching shear strength of glass fiber-reinforced polymer reinforced concrete flat slabs. Canadian Journal of Civil Engineering, 40(10), 951-960.
[7] Dulude, C., Hassan, M., Ahmed, E. A., and Benmokrane, B. (2013). Punching shear behavior of flat slabs reinforced with glass fiber-reinforced polymer bars. ACI Structural Journal, 110(5), 723-734.
[8] American Concrete Institute. Committee 440. (2003). Guide for the Design and Construction of Concrete Reinforced with FRP Bars: ACI 440.1 R-03. American Concrete Institute.
[9] Ahmed, E. A., Benmokrane, B., and Sansfaçon, M. (2017). Case study: Design, construction, and performance of the La Chancelière parking garage’s concrete flat slabs reinforced with GFRP bars. Journal of Composites for Construction, 21(1), 1-15.
[10] Gouda, A., El-Salakawy, E. (2016). Punching shear strength of GFRP-RC interior slab–column connections subjected to moment transfer. Journal of Composites for Construction, 20(1), 1-12.
[11] Gouda, A., El-Salakawy, E. (2016). Punching shear strength of GFRP-RC interior slab–column connections subjected to moment transfer. Journal of Composites for Construction, 20(1), 1-11.
[12] Salama, A. E., Hassan, M., Benmokrane, B., and Ferrier, E. (2020). Modified strip model for punching-shear strength of FRP-reinforced concrete edge–column slab connections. Engineering Structures, 216, 1-13.
[13] Drakatos, I. S., Muttoni, A., Beyer, K. (2016). Internal slab-column connections under monotonic and cyclic imposed rotations. Engineering Structures, 123, 501-516.
[14] Milligan, G. J., Polak, M. A., Zurell, C. (2020). Finite element analysis of punching shear behaviour of concrete slabs supported on rectangular columns. Engineering Structures, 224, 1-13.
[15] ABAQUS, G. (2020). Dassault Systemes Simulia Corporation, Providence, RI, USA.
[16] American Concrete Institute, ACI Committee 440. (2015). Guide for the Design and Construction of Structural Concrete Reinforced with Fiber-Reinforced Polymer (FRP) Bars, 440R.1R, Farmington Hills, MI.
[17] Canadian Standards Association, CAN/CSA S806-12 (2017). Design and construction of building structures with fibre-reinforced polymers, Rexdale, ON, Canada.
[18] Japan Society of Civil Engineers, JSCE (1997). Recommendation for Design and Construction of Concrete Structures Using Continuous Fiber Reinforcing Materials. Concrete Engineering, A. Machida, ed., Tokyo, Japan.
[19] British Standards Institution, BSI (1997). Structural Use of Concrete, BS 8110: Part 1—Code of Practice for Design and Construction. London, UK.
[20] Nguyen-Minh, L., and Rovňák, M. (2013). Punching shear resistance of interior GFRP reinforced slab-column connections. Journal of Composites for Construction, 17(1), 2-13.
[21] Salama, A. E., Hassan, M., and Benmokrane, B. (2021). Punching-Shear Behavior of Glass Fiber-Reinforced Polymer-Reinforced Concrete Edge Column-Slab Connections: Experimental and Analytical Investigations. ACI Structural Journal, 118(3), 147-160.
[22] Gołdyn, M., Urban, T. (2020). Effect of load level of corner columns on punching shear resistance of flat slabs. Budownictwo i Architektura, 19(3).
 [23] Mander, J. B., Priestley, M. J., and Park, R. (1988). Theoretical stress-strain model for confined concrete. Journal of structural engineering, 114(8), 1804-1826.
[24] Genikomsou, A. S., Polak, M. A. (2015). Finite element analysis of punching shear of concrete slabs using damaged plasticity model in ABAQUS. Engineering structures, 98, 38-48.
[25] Bompa, D. V., Elghazouli, A. Y. (2020). Nonlinear numerical simulation of punching shear behavior of reinforced concrete flat slabs with shear-heads. Frontiers of Structural and Civil Engineering, 14(2), 331-356.
[26] Abdulrahman, B. Q., Wu, Z., Cunningham, L. S. (2017). Experimental and numerical investigation into strengthening flat slabs at corner columns with externally bonded CFRP. Construction and Building Materials, 139, 132-147.
[27] Afifi, M. Z., Mohamed, H. M., Benmokrane, B. (2014). Strength and axial behavior of circular concrete columns reinforced with CFRP bars and spirals. Journal of Composites for Construction, 18(2), 1-10.
[28] El-Ghandour, A. W., Pilakoutas, K., Waldron, P. (2003). Punching shear behavior of fiber reinforced polymers reinforced concrete flat slabs: experimental study. Journal of Composites for Construction7(3), 258-265.
[29] El-Gendy, M. G., El-Salakawy, E. F. (2021). Finite-element analysis of FRP-reinforced concrete slab–column edge connections subjected to reversed-cyclic lateral loads. Journal of Composites for Construction, 25(1), 1-18.
[30] Drakatos, I. S., Muttoni, A., Beyer, K. (2018). Mechanical model for drift-induced punching of slab-column connections without transverse reinforcement. ACI Structural Journal, 115, 463-474.