ارزیابی رفتار پیوستگی-لغزش در اتصالات تیر به ستون بتن مسلّح پیش‌ساخته با استفاده از مدل‌سازی اجزاء محدود

نوع مقاله : علمی - پژوهشی

نویسندگان

1 گروه مهندسی عمران دانشگاه شهید باهنر کرمان، کرمان، ایران

2 استاد، دانشکده فنی و مهندسی، دانشگاه شهید با هنر کرمان

چکیده

در این مقاله، یک راهکار برای مدل‌سازی عددی رفتار پیوستگی-لغزش میلگرد مدفون در بتن پیشنهاد شد. بدین منظور، یک نمونه ی ساده ی آزمایشگاهی میلگرد مدفون در بتن از مراجع معتبر انتخاب گردید. مدل‌سازی اجزاء محدود نمونه ی مذکور در نرم‌افزار آباکوس انجام شد و پس از مقایسه ی نتایج حاصل از تحلیل اجزاء محدود با نتایج حاصل از آزمایشگاه، صحت مدل پیشنهادی مورد تائید قرار گرفت. سپس یک نمونه ی اتصال تیر به ستون بتن مسلّح درجاریز و یک نمونه ی اتصال تیر به ستون بتن مسلّح پیش‌ساخته از مراجع معتبر انتخاب گردید و به روش اجزاء محدود مدل‌سازی شدند. راهکار پیشنهادی برای مدل‌سازی لغزش میلگرد در نمونه ی اتصال پیش‌ساخته پیاده سازی شد. پس از اتمام مدل‌سازی و صحت سنجی نتایج حاصل از تحلیل اجزاء محدود نمونه‌ها، برای بهبود رفتار نمونه ی اتصال پیش‌ساخته از وصله ی مکانیکی برای جلوگیری از لغزش میلگرد طولی تیر استفاده شد. این اصلاح در نمونه ی اتصال پیش‌ساخته، منجر به بهبود رفتار اتصال شامل افزایش بار تسلیم و بار نهایی اتصال نسبت به نمونه ی اتصال پیش‌ساخته و حتی نمونه ی اتصال درجاریز شد؛ اما نسبت لنگر نهایی وارد بر مقطع به مقاومت خمشی مقطع در نمونه ی درجاریز و نمونه ی پیش‌ساخته ی اصلاح شده تقریباً برابر و نزدیک به عدد یک بود که این خود بیانگر رسیدن لنگر در مقطع به حداکثر ظرفیت خود و تشکیل مفصل پلاستیک خمشی در مقطع است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Evaluation of bond-slip behavior in precast reinforced concrete beam-to-column connection using finite element modeling

نویسندگان [English]

  • Amin Iranpour 1
  • Houman Ebrahimpour 1
  • Reza Rahgozar 2
1 Department of Civil Engineering, Shahid bahonar University of Kerman, Kerman, Iran
2 Professor, Department of Civil Engineering, Faculty of Engineering, Shahid Bahonar University of Kerman
چکیده [English]

In this paper, in order to numerically model the bond-slip behavior of embedded bars, an applicable procedure was proposed. To evaluate the efficiency of the proposed model, a credible experimental specimen was selected and modeled in Abaqus software. Comparing the numerical and experimental results of the specimen confirmed the acceptable accuracy of the proposed model. Afterwards, two monolithic and precast reinforced concrete beam-to-column connections were chosen from experimental tests and were numerically simulated. Investigation on the precast specimen showed that the required embedded length of longitudinal bars of beam was not considered. Hence, slippage of the longitudinal bars of the beam at the connection area led to degradation of connection strength. In order to consider this slippage in finite element modeling, the proposed approach was employed. Analytical results showed a suitable agreement with experimental ones and slippage of the beam bars was observed in the finite element analysis. Consequently, in order to prevent the slippage of beam bars, couplers at the end of the bars were used. Required area of the couplers was calculated as such to develop yielding in longitudinal beam bars. These couplers were added to the precast specimen and afterward, this specimen was named modified-precast specimen. Capacity of the modified-precast specimen including yielding load, ultimate load and ductility was improved in comparison with monolithic and precast specimen. However, the ratios of ultimate moment to flexural strength in modified-precast and monolithic specimens are approximately equal to one, which shows the formation of flexural plastic hinge in the beams of both modified-precast and monolithic specimens.

کلیدواژه‌ها [English]

  • Precast concrete
  • beam-to-column connection
  • finite element modeling
  • bond-slip behavior
  • Mechanical anchorage
[1] ACI 318, (2014). Building code requirements for structural concrete (ACI 318-14) and commentary. Farmington Hills: American Concrete Institute.
[2] Metelli, G. and Riva, P. (2008). Behaviour of a beam to column “dry” joint for precast Concrete elements. In: The 14th World Conference on Earthquake Engineering.
[3] Vidjeapriya, R. and Jaya, K. (2012). Experimental study on two simple mechanical precast beam-column connections under reverse cyclic loading. Journal of Performance of Constructed Facilities, 27 (4), 402-414.
[4] Negro, P., Bournas, D.A. and Molina, F.J. (2013). Pseudodynamic tests on a full-scale 3-storey precast concrete building: global response. Engineering structures, 57, 594-608.
[5] Bournas, D.A., Negro, P. and Molina, F.J. (2013). Pseudodynamic tests on a full-scale 3-storey precast concrete building: behavior of the mechanical connections and floor diaphragms. Engineering structures, 57, 609-627.
[6] Negro, P. and Toniolo, G. (2012). Design Guidelines for Connections of Precast Structures under Seismic Actions.
[7] Viwathanatepa, S., Popov, E.P. and Bertero, V.V. (1979). Effects of generalized loadings on bond of reinforcing bars embedded in confined concrete blocks. University of California, Earthquake Engineering Research Center.
[8] Eligehausen, R., Popov, E.P. and Bertero, V.V. (1982). Local bond stress-slip relationships of deformed bars under generalized excitations.
[9] CEB-FIP, (1990). Model Code for Concrete Structures.
[10] CEB-FIP, (2010). Model Code for Concrete Structures.
[11] Lowes, L.N., Mitra, N. and Altoontash, A. (2003). A beam-column joint model for simulating the earthquake response of reinforced concrete frames. Pacific Earthquake Engineering Research Center, College of Engineering, University of California Berkeley.
[12] Cheok, G.S. and Lew, H.S. (1991). Performance of 1/3-scale Model Precast Concrete Beam-column Connections Subjected to Cyclic Inelastic Loads: Report No. 2. US National Institute of Standards and Technology.
[13] Hawileh, R., Rahman, A. and Tabatabai, H. (2010). Nonlinear finite element analysis and modeling of a precast hybrid beam–column connection subjected to cyclic loads. Applied Mathematical Modelling, 34 (9), 2562-2583.
[14] Standard.432.1.1982, I., Specification For Mild Steel And Medium Tensile Steel Bars And Hard-Drawn Steel wire For Concrete Reinforcement.
[15] Standard.1786.2008, I., High Strength Deformed Steel Bars and Wires for Concrete Reinforcement.
[16] Zha X, Wan C, Yu H, Dassekpo J-BM. (2016). Seismic behavior study on RC-beam to CFST-column non-welding joints in field construction. Journal of Constructional Steel Research, 116, 204-17.
[17] Breccolotti M, Gentile S, Tommasini M, Materazzi AL, Bonfigli MF, Pasqualini B, Colone, V, Gianesini, M. (2016). Beam-column joints in continuous RC frames: Comparison between cast-in-situ and precast solutions. Engineering Structures, 127, 129-44.
[18] Abaqus 6.13. (2013). Analysis User’s Manual.
[19] Hsu, L. and Hsu, C.T. (1994). Complete stress—strain behaviour of high-strength concrete under compression. Magazine of Concrete Research, 46 (169), 301-312.
[20] 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.
[21] Li Y, Cao S, Jing D. (2018). Analytical compressive stress–strain model for concrete confined with high‐strength multiple‐tied‐spiral transverse reinforcement. The Structural Design of Tall and Special Buildings, 27(2).
[22] Patel VI, Hassanein M, Thai H-T, Al Abadi H, Paton-Cole V. (2017). Behaviour of axially loaded circular concrete-filled bimetallic stainless-carbon steel tubular short columns. Engineering Structures, 147, 583-97.
[23] Zeng X. (2017). Finite element analysis of the behaviour of reinforced concrete columns confined by overlapping hoops subjected to rapid concentric loading. Civil Engineering Journal-Stavebni Obzor, 4, 530-43.
[24] Birtel, V. and Mark, P. (2006). Parameterised finite element modelling of RC beam shear failure. In: ABAQUS Users’ Conference.
[25] Gan, Y. (2000). Bond stress and slip modeling in nonlinear finite element analysis of reinforced concrete structures. MSc thesis. University of Toronto.
[26] Elmorsi, M., Kianoush, M.R. and Tso, W. (2000). Modeling bond-slip deformations in reinforced concrete beam-column joints. Canadian Journal of Civil Engineering, 27 (3), 490-505.
[27] Ožbolt, J., Lettow, S. and Kožar, I. (2002). Discrete bond element for 3D finite element analysis of reinforced concrete structures. In: Proceedings of the 3rd International Symposium: Bond in Concrete-from research to standards. Budapest: University of Technology and Economics.
[28] Gooranorimi O, Suaris W, Nanni A. (2017). A model for the bond-slip of a GFRP bar in concrete. Engineering Structures, 146:34-42.
[29] Alfarah B, Murcia‐Delso J, López‐Almansa F, Oller S. (2018). RC structures cyclic behavior simulation with a model integrating plasticity, damage, and bond‐slip. Earthquake Engineering & Structural Dynamics, 47(2), 460-78.
[30] Hwang J-y, Kwak H-G, Kwon Y. (2018). A numerical model for considering the bond-slip effect in axially loaded circular concrete-filled tube columns. Advances in Structural Engineering, 1369433218759779.
[31] Nzabonimpa J, Hong W-K, Kim J. (2017). Nonlinear finite element model for the novel mechanical beam-column joints of precast concrete-based frames. Computers & Structures, 189, 31-48.
[32] Wang C, Shen Y, Yang R, Wen Z. (2017). Ductility and Ultimate Capacity of Prestressed Steel Reinforced Concrete Beams. Mathematical Problems in Engineering, 2017.
[33] Chaudhari, S. and Chakrabarti, M. (2012). Modeling of concrete for nonlinear analysis Using Finite Element Code ABAQUS. International Journal of Computer Applications, 44 (7), 14-18.
[34] Zhou X, Cheng G, Liu J, Gan D, Chen YF. (2017). Behavior of circular tubed-RC column to RC beam connections under axial compression. Journal of Constructional Steel Research, 130, 96-108.
[35] Ning N, Qu W, Ma ZJ. (2016). Design recommendations for achieving “strong column-weak beam” in RC frames. Engineering Structures, 126, 343-52.
[36] El Ezz AA, Galal K. (2017). Compression behavior of confined concrete masonry boundary elements. Engineering Structures, 132, 562-75.
[37] Tang X-L, Cai J, Chen Q-J, Liu X, He A. (2016). Seismic behaviour of through-beam connection between square CFST columns and RC beams. Journal of Constructional Steel Research, 122, 151-66.
[38] Sucuoǧlu, H. (1995). Inelastic seismic response of precast concrete frames with constructed plastic hinges. Computers & structures, 56 (1), 121-131.