مطالعه‌ی آزمایشگاهی رفتار خمشی تیر‌های بتنی پیش‌تنیده تحت تاثیر خوردگی تسریع شده

نوع مقاله : علمی - پژوهشی

نویسندگان

1 دانشجوی دکتری، دانشکده مهندسی، دانشگاه بوعلی سینا، همدان، ایران.

2 دانشیار، دانشکده مهندسی، دانشگاه بوعلی سینا، همدان، ایران.

چکیده

یکی از عوامل خرابی زودرس سازه‌های بتن آرمه، خوردگی فولاد‌های آن است و این موضوع به‌ویژه در سازه‌های با حساسیت بالا‌تر همچون سازه‌های پیش‌تنیده که فولاد‌های پیش‌تنیدگی، نقش به‌مراتب مهم‌تری را در باربری سازه ایفا می‌کنند، اهمیت بیشتری پیدا می‌کند. در این پژوهش یک مطالعه‌ی آزمایشگاهی به‌منظور ارزیابی رفتار خمشی تیر‌های بتنی پیش‌تنیده تحت تاثیر خوردگی صورت گرفت و برای این منظور ٤ نمونه تیر بتنی پیش‌تنیده پیش‌کشیده با مقطع مستطیلی به ابعاد ٣٠٠×١۵٠ میلی‌متر و طول ٢ متر ساخته شد. روش ایجاد خوردگی در تیرهای بتنی پیش‌تنیده به‌صورت تسریع شده با استفاده از جریان الکتریکی ثابت در کابل‌های پیش‌تنیدگی و در یک استخر حاوی محلول الکترولیت ۵ درصد آب‌نمک بود. یک تیر بتنی پیش‌تنیده بدون خوردگی و به عنوان نمونه شاهد در نظر گرفته شد و در سه تیر موردمطالعه دیگر خوردگی در سه سطح ۵، ١٠ و ١۵ درصد ایجاد شد. بعد از ایجاد خوردگی، نمونه‌ها جهت بررسی رفتار سازه‌ای تحت آزمایش بارگذاری خمشی به روش چهارنقطه‌ای قرار گرفتند. نتایج نشان داد که خوردگی باعث کاهش ظرفیت باربری و سایر مشخصات رفتاری نمونه مورد‌مطالعه از‌جمله میزان جذب انرژی، سختی موثر و خیز وسط دهانه می‌شود. با افزایش سطح خوردگی، روند کاهشی پارامتر‌های مورد بررسی افزایش می‌یابد. در بالا‌ترین سطح خوردگی (سطح ١۵درصد) مقادیر پارامتر‌های ظرفیت باربری، انرژی جذب شده، سختی موثر و خیز وسط دهانه به ترتیب ٢٤، ٣٤، ٣٧ و ١٩ درصد کاهش یافتند. همچنین بررسی‌ها نشان داد، توزیع خوردگی ایجاد شده به روش تسریع شده در طول کابل‌های پیش‌تنیدگی غیر یکنواخت است و بین میزان خوردگی ایجاد شده عملی و محاسباتی بر مبنای قانون فارادی تفاوت وجود دارد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Experimental investigation on the flexural behavior of prestressed concrete beams under the influence of accelerated corrosion

نویسندگان [English]

  • pouya hassanvand 1
  • Freydoon Rezaie 2
1 Ph.D student, Faculty of Engineering, Bu-Ali Sina University, Hamedan, Iran.
2 Associate Professor, Faculty of Engineering, Bu-Ali Sina University, Hamedan, Iran.
چکیده [English]

One of the early deterioration factors of reinforced concrete structures is the corrosion of its steels, and in structures with greater sensitivity, such as prestressed structures, where steel elements, including prestressed tendons, play a much larger role in supporting the structure, the importance of this issue increases. In this research, an experimental evaluation of the flexural behavior of prestressed concrete beams under the influence of corrosion. To this end, four prestressed concrete beams with a rectangular cross-section (150 mm × 300 mm) and a length of 2 m were fabricated. The method for causing corrosion in specimens was accelerated by using constant electric current in prestressing tendons and in a pool containing 5% sodium chloride electrolyte solution. One prestressed concrete beam without corrosion was considered as a control specimen, and in the other three studied beams, corrosion occurred at three levels of 5, 10 and 15%. After exposure corrosion, the specimens were subjected to four-point bending test in order to check the structural behavior. The results indicated that the corrosion created at different levels reduced the bearing capacity and other behavioral characteristics of the specimen under study, including the amount of energy absorption, effective hardness and midspan displacement. Increase of the corrosion level, increases the decreasing trend of the studied parameters. At the highest level of corrosion (15% level), the values of the parameters of bearing capacity, absorbed energy, effective hardness, and mid-span deflection decreased by 24%, 34%, 37%, and 19%, respectively. Also, the investigations showed that there is a non-uniform distribution of corrosion caused by the accelerated method along the prestressing cables and difference between the actual and calculated corrosion rates based on the Faraday's law.

کلیدواژه‌ها [English]

  • Prestressed concrete beam
  • Flexural behavior
  • Corrosion
  • Bearing capacity
  • Structural behavior

مراجع

[1] Azad, A.K., Ahmad, S., & Azher, S.A. (2007). Residual strength of corrosion-damaged reinforced concrete beams. ACI Materials Journal, 104(1), 40-47.
[2] Lachemi, M., Al-Bayati, N., Sahmaran, M., & Anil. O. (2014). The effect of corrosion on shear behavior of reinforced self-consolidating concrete beams. Engineering Structures, 79, 1-12.
[3] Campione, G., Cannella, F., & Cavaleri, L. (2017). Shear and flexural strength prediction of corroded R.C. beams. Construction and Building Material, 149, 395-405.
[4] Fang, C., Lundgren, K., Plos, M., & Gylltoft, K. (2006). Bond behavior of corroded reinforcing steel bars in concrete. Cement and Concrete Research, 36, 1931-1938.
[5] Zhao, Y., Xu, X., Wang, Y., & Dong, J. (2020). Characteristics of pitting corrosion in an existing reinforced concrete beam exposed to marine environment. Construction and Building Material, 234, 117392.
[6] Liu, Y., & Weyers, R.E. (1998). Modeling the time-to-corrosion cracking in chloride contaminated reinforced concrete structures. ACI Materials Journal, 96(6), 675-681.
[7] Andrade, C., Alonso, C., & Molina, F.J. (1993). Cover cracking as a function of rebars corrosion: Part 1—Experimental test. Materials and Structures, 26(8), 453-464.
[8] Williamson, S.J., & Clark, L.A. (2000). Pressure required to cause cover cracking of concrete due to reinforcement corrosion. Magazine of Concrete Research, 52(6), 455-467.
[9] Al-Sulaimani, G.J., Kaleemullah, M., Basunbul, I.A., & Rasheeduzzafar. (1990). Influence of corrosion and cracking on bond behavior and strength of reinforced concrete members. ACI Structural Journal, 87(2), 220-230.
[10] Amleh, L., & Mirza, A. (1999). Corrosion influence on bond between steel and concrete. ACI Structural Journal, 96(3), 415-423. 
[11] Kivell, A., Palermo, A., & Scott, A. (2011). Effects of bond deterioration due to corrosion in reinforced concrete. In: Proceedings of ninth Pacific conference on earthquake engineering building an earthquake-resilient society. Auckland (New Zealand), 14–16.
[12] Kivell, A., Palermo, A., & Scott, A. (2015). Complete model of corrosion-degraded cyclic bond performance in reinforced concrete. Journal of Structural Engineering, 141(9), 04014222.
[13] Sajedi, S., & Huang, Q. (2015). Probabilistic prediction model for average bond strength at steel–concrete interface considering corrosion effect. Engineering Structures, 99, 120-131.
[14] Meda, A., Mostosi, S., Rinaldi, Z., & Riva, P. (2014). Experimental evaluation of the corrosion influence on the cyclic behaviour of RC columns. Engineering Structures, 76, 112-123.
[15] Yu, L., François, R., Dang, V.H., L’Hostis, V., & Gagné, R. (2015). Structural performance of RC beams damaged by natural corrosion under sustained loading in a chloride environment. Engineering Structures, 96, 30-40.
[16] Khaloo, A. (2017). Design of prestressed concrete structures. Second edition. Tehran: Publication Center of Sharif University of Technology.
[17] Kioumarsi, M., Benenato, A.; Ferracuti, B.; Imperatore, S. (2021). Residual flexural capacity of corroded prestressed reinforced concrete beams. Metals, 11, 442.
[18] Coronelli, D., Castel, A., Vu, N.A., & François, R. (2009). Corroded post-tensioned beams with bonded tendons and wire failure. Engineering Structures, 31(8), 1687–1697.
[19] Rinaldi, Z., Imperatore, S., & Valente, C. (2010). Experimental evaluation of the flexural behavior of corroded P/C beams. Construction and Building Material, 24(11), 2267–2278.
[20] Castel, A., François, R., & Coronelli, D. (2012). Response of corroded prestressed beams with bonded strands. Ice Proceedings Structures and Buildings, 165(5), 233–244.
[21] Rogers, R., Wotherspoon, L., Scott, A. N., & Ingham, J. M. (2012). Residual strength assessment and destructive testing of decommissioned concrete bridge beams with corroded pretensioned reinforcement.
[22] Melchers, R.E., & Pape, T.M. (2013). Performance of 45-year-old corroded prestressed concrete beams. Proc. Ice Structures and Buildings, 166(10), 547–559.
[23] Wang, L., Zhang, X., Zhang, J., Ma, Y., Xiang, Y., & Liu, Y. (2014). Effect of insufficient grouting and strand corrosion on flexural behavior of PC beams. Construction and Building Material, 53, 213–224.
[24] Yu, Q. Q., Gu, X. L.; Zeng, Y. H.; Zhang, W. P. (2022). Flexural behavior of Corrosion-Damaged prestressed concrete beams. Eng. Struct, 272, 114985.
[25] Moawad, M., Mahmoud, M., El-karmoty, H., & El-zanaty, A. (2018). Behavior of corroded bonded partially prestressed concrete beams. Housing and Building National Research center, 14(1), 9-21.
[26] Jeon, C.-H., Le, J.-B., Lon, S., & Shim, C.-S. (2019). Equivalent material model of corroded prestressing steel strand. Journal of Materials Research and Technology, 8(2), 2450-2460.
[27] Tamai, H., Sonoda, Y., & Bolander, J.E. (2020). Impact resistance of RC beams with reinforcement corrosion: Experimental observations. Engineering Structures, 263, 120638.
[28] Nasser, H., Steen, CH.V., Vandewalle, L., & Verstrynge, E. (2021). An experimental assessment of corrosion damage and bending capacity reduction of singly reinforced concrete beams subjected to accelerated corrosion. Engineering Structures, 286, 122773.
[29] Taqi, F.Y., Mashrei, M.A., & Oleiwi, H.M. (2021). Experimental study on the effect of corrosion on shear strength of fibre-reinforced concrete beams. Structures, 33, 2317-2333.
[30] ape, T. M., Melchers, R. E. (2013). Performance of 45-year-old corroded prestressed concrete beams. Structures and Buildings, 166, 547-559.
[31] ACI 318-19. (2019). Building Code Requirements for Structural Concrete. Reported by ACI Committee 318, ACI Standard.
[32] ASTM Standard C150-07. (2012). Standard Specification for Portland Cement. ASTM.
[33] ASTM Standard C494/C494M-17. (2020). Standard Specification for Chemical Admixtures for Concrete, ASTM.
[34] ASTM Standard A421/A421M-21. (2021). Standard Specification for Stress-Relieved Steel Wire for Prestressed Concrete, ASTM.
[35] Maaddawy, T.E., & Soudki, Kh.A. (2003). Effectiveness of impressed current technique to simulate corrosion of steel reinforcement in concrete. Journal of Materials in Civil Engineering, 15(1), 41-47.
[36] Zhang, W., Liu, X.; Gu, X. (2016). Fatigue behavior of corroded prestressed concrete beams. Construction and Building Materials, 106, 198-208.
[37] Paulay, T., Priestly, M.J.N. Seismic design of reinforced concrete and masonry buildings, 1st Edition.; Publisher by wiley-interscience, New York, 1992.

فایل ها

سابقه مقاله

  • تاریخ دریافت: 16 دی 1401
  • تاریخ بازنگری: 25 بهمن 1401
  • تاریخ پذیرش: 30 بهمن 1401

هم رسانی

ارجاع به این مقاله

آمار