Analysis of Strength Reduction Factor for Axially-Loaded Circular Columns with Fiber Reinforced Polymer

Öz

The code and regulations use strength reduction factors to take into account the uncertainties of the random variables considered in structural design. In this study, for plain concrete columns and reinforced concrete columns (tie-reinforced column) wrapped with carbon fiber polymer (CFRP) under axial load obtained from literature, the strength reduction factors (ϕ) were calculated according to second-order moment approach by taking into account the target reliability index (β) and, different coefficient of variation of random variables of performance function [1]. In the calculations, the target reliability index was taken β=3.5 and the corresponding probability of failure as p_F=2.33〖*10〗^(-4). In ACI 318-19, the strength reduction factors for plain column and tie-reinforced column under axial load are 0.60 and 0.65, respectively. As a result of study, the strength reduction factors recommended in the ACI 318-19 for columns reinforced with fiber polymer were compared with the strength reduction factors obtained for different coefficient of variation.

Anahtar Kelimeler

• Strength reduction factor
• target reliability
• fiber polymer
• second moment approach
• probabilistic design

Eksenel Yük Altındaki Lifli Polimer İle Sargılı Dairesel Enkesitli Kolonlarda Dayanım Azaltma Katsayısının İncelenmesi

Öz

Yönetmeliklerde, yapısal tasarımda göz önüne alınan rasgele değişkenlerin belirsizliklerini hesaba katmak için dayanım azaltma katsayıları kullanılır. Bu amaçla, çalışma kapsamında literatürden elde edilen karbon lifli polimer (CFRP) ile sargılı, boyuna ve enine donatılı (dairesel etriye) ve donatısız eksenel yük etkisindeki kolon numuneleri için, hedef güvenilirlik indeksi (β) ve performans fonksiyonunu oluşturan rasgele değişkenlere ilişkin farklı varyasyon katsayıları göz önüne alınarak ikinci moment yaklaşımına göre dayanım azaltma katsayıları (ϕ) hesaplanmıştır [1]. Hesaplamalarda, β=3.5 ve buna karşılık gelen göçme olasılığı değeri p_F=2.33〖*10〗^(-4) olarak alınmıştır. ACI 318-19 yönetmeliğinde, eksenel yük etkisindeki donatısız kolonlar ve etriyeli kolonlar için dayanım azaltma katsayısının değerleri sırasıyla 0.60 ve 0.65 olarak önerilmiştir. Çalışma sonucunda lifli polimerle güçlendirilmiş kolonlar için ACI 318-19 yönetmeliğinde önerilen dayanım azaltma katsayısı değerleri, farklı varyasyon katsayıları için elde edilen dayanım azaltma katsayısı değerleri ile karşılaştırılmıştır.

Anahtar Kelimeler

• Dayanım Azaltma Katsayısı
• Hedef güvenilirlik indeksi
• lifli polimer
• ikinci moment yaklaşımı
• olasılıksal tasarım

Kaynakça

1. [1] Tarawneh A., Sereen Majdalaweyh S., (2020). Design and reliability analysis of FRP-reinforced concrete columns, Structures, Cilt 28, s.1580-1588. DOI:10.1016/j.istruc.2020.10.009
2. [2] Xiao Y., Wu H., 2000. Compressive Behavior of Concrete Confined by Carbon Fiber Composite Jackets, Journal of Materials in Civil Engineering, Cilt. 12(2), s. 139-146. DOI: 10.1061/(ASCE)0899-1561(2000)12:2(139)
3. [3] Zou Y., Hong H.P., 2008. Reliability Assessment of FRP-Confined Columns Designed for Buildings, Structure and Infrastructure Engineering, Cilt. 7(3), s. 243-258. DOI: 10.1080/15732470802416998
4. [4] Alqam M., Bennett R.M., Zureick A-H. 2004. Probabilistic Based Design of Concentrically Loaded Fiber-Reinforced Polymeric Compression Members, Journal of Structural Engineering, Cilt. 130(12), s. 1914-1920. DOI: 10.1061/(ASCE)0733-9445(2004)130:12(1914)
5. [5] Yingwu Z., Feng X., Lili S. (2013). Reliability Assessments of Concrete Filled FRP Tube Columns, Applied Mechanics and Materials, Cilt 405-408, s.731-734. DOI: 10.4028/www.scientific.net/AMM.405-408.731
6. [6] Mirza S.A. 1996. Reliability-Based Design of Reinforced Concrete Columns, Structural Safety, Cilt. 18(2), s. 179-194. DOI: 10.1016/0167-4730(96)00010-0
7. [7] Arslan, G., Alacalı, S. N., Sağıroğlu, A. 2015. The Investigation of the Strength Reduction Factor in Predicting the Shear Strength, Journal of Theoretical and Applied Mechanics (JTAM), Cilt. 53(2), s. 371-381. DOI: 10.15632/jtam-pl.53.2.371
8. [8] Arslan, G., Alacalı, S., Sağıroğlu, A. 2016. Assessing Reduction in Concrete Shear Strength Contribution, Proceedings of the Institution of Civil Engineers - Structures and Building, Cilt. 169(4),s. 237-244. DOI: 10.1680/jstbu.14.00102

9. [9] Alacalı, S., Arslan, G., 2018. Assessment of the Strength Reduction Factor in Predicting the Flexural Strength, Journal of Theoretical and Applied Mechanics, Cilt. 56(4) s. 1043-1053. DOI: 10.15632/jtam-pl.56.4.1043
10. [10] American Concrete Institute Committee 318 (ACI318), 2005. Building Code Requirements for Structural Concrete (ACI 318-05) and Commentary, Farmington Hills, MI
11. [11] American Concrete Institute Committee 318 (ACI318), 2014. Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary, Farmington Hills, MI
12. [12] American Concrete Institute Committee 318 (ACI318), 2019. Building Code Requirements for Structural Concrete (ACI 318-19) and Commentary, Farmington Hills, MI
13. [13] American Concrete Institute Committee 440 (440.2R-17), 2017. Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures, Farmington Hills, MI
14. [14] Ang A.H.S., Tang W.H., 1984. Probability Concepts in Engineering Planning and Design, Cilt. 2-Decision, Risk and Reliability, Wiley, NY
15. [15] Hao H., Li Z.X., Shi Y. 2015. Reliability Analysis of RC Columns and Frame with FRP Strengthening Subjected to Explosive Loads, Journal of Performance of Constructed Facilities, 04015017, DOI: 10.1061/(ASCE)CF.1943-5509.0000748
16. [16] Ali O. 2017. Structural Reliability of Biaxial Loaded Short/Slender-Square FRP-Confined RC Columns, Construction and Building Materials, Cilt. 151, s. 370-382. DOI: 10.1016/ j.conbuildmat.2017.06.032
17. [17] Jafari F. 2014. Reliability of FRP Reinforced Concrete Columns, 1. Persian Gulf International Conference on Sustainable Concrete, 17-18 December, Bandar Abbas
18. [18] Val D., Bljuger F., Yankelevsky D. 1997. Reliability Evaluation in Nonlinear Analysis of Reinforced Concrete Structures, Structural Safety, Cilt. 19, s. 203-217. DOI: 10.1016/S0167-4730(96)00025-2
19. [19] Atadero R.A., Karbhari V. M. 2007. Calibration of Resistance Factors for Reliability Based Design of Externally Bonded FRP Composites, Composites: Part B, Cilt. 39, s. 665-679. DOI: 10.1016/j.compositesb.2007.06.004
20. [20] Hong H.P., Zhou W. 1999. Reliability Evaluation of RC Columns, Journal of Structural Engineering, Cilt. 125(7), s. 784-790. DOI: 10.1061/(ASCE)0733-9445(1999)125:7(784)
21. [21] Monti G., Santini S. 2002. Reliability Based Calibration of Partial Safety Coefficient for Fiber-Reinforced Plastic, Journal of Composites for Construction, Cilt. 6(3), s. 162-167. DOI: 10.1061/(ASCE)1090-0268(2002)6:3(162)
22. [22] Kim J.H., Lee S.H., Paik I., Lee H.S. 2015. Reliability Assessment of Reinforced Concrete Columns Based on the P-M Interaction Diagram Using AFOSM, Structural Safety, Cilt. 55, s. 70-79. DOI: 10.1016/j.strusafe.2015.03.003
23. [23] Val D.V. 2003. Reliability of Fiber-Reinforced Polymer-Confined Reinforced Concrete Columns, Journal of Structural Engineering, Cilt. 129(8), s. 1122-1130. DOI: 10.1061/(ASCE)0733-9445(2003)129:8(1122)
24. [24] Taki A., Firouzi A., Mohammadzadeh S. 2018. Life Cycle Reliability Assessment of Reinforced Concrete Beams Shear-Strengthened with Carbon Fiber Reinforced Polymer Strips in Accordance with Fib Bulletin 14, Structural Concrete, Cilt. 19(6), s. 2017-2028. DOI: 10.1002/suco.201700289
25. [25] Wieghaus K.T., Atadero R.A. 2011. Effect of Existing Structure and FRP Uncertainties on the reliability of FRP-Based Repair, Journal of Composites for Construction, Cilt. 15(4), s. 635-643. DOI: 10.1061/(ASCE)CC. 1943-5614.0000197
26. [26] Okeil A.M., El-Tawil S., Shahawy M. 2002. Flexural Reliability of Reinforced Concrete Bridge Girders Strengthened with Carbon Fiber-Reinforced Polymer Laminates, Journal of Bridge Engineering, Cilt. 7(5), s. 290-299. DOI: 10.1061/(ASCE)1084-0702(2002)7:5(290)
27. [27] Ruiz S.E., Aguilar J.C. 1994. Reliability of Short and Slender Reinforced-Concrete Columns, Journal of Structural Engineering, Cilt. 120, DOI:10.1061/(ASCE)0733-9445(1994)120:6(1850)
28. [28] Jiang Y., Yang W. 2012. An Approach Based on Theorem of Total Probability for Reliability Analysis of RC Columns with Random Eccentricity, Structural Safety, Cilt. 41, s. 37-46. DOI: 10.1016/j.strusafe.2012.11.001
29. [29] Chastre C., Silva M.A.G., 2010. Monotonic Axial Behavior and Modelling of RC Circular Columns Confined with CFRP, Engineering Structures, Cilt. 32, s. 2268-2277. DOI: 10.1016/j.engstruct.2010.04.001
30. [30] Benzaid R., Mesbah H.A., 2014. The Confinement of Concrete in Compression Using CFRP Composites-effective Design Equations, Journal of Civil Engineering and Management, Cilt. 20(5), s. 632-648. DOI: 10.3846/13923730.2013.801911
31. [31] Faustino P., Chastre C., Paula R., 2013. Design Model for Square RC Columns under Compression Confined with CFRP, Composites: Part B, Cilt. 57, s. 187-198. DOI: 10.1016/j.compositesb.2013.09.052
32. [32] Peker Ö., 2005, Düşük Dayanımlı Betonarme Elemanların CFRP ile Güçlendirilmesi, İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, Yüksek Lisans Tezi, İstanbul
33. [33] Lin C.T., Li Y.F., 2003. An Effective Peak Stress Formula for Concrete Confined with Carbon Fiber Reinforced Plastics, Canadian Journal of Civil Engineering, Cilt. 30, s. 882-889. DOI: 10.1139/L03-047
34. [34] Karabinis A.I., Rousakis T.C., 2002. Concrete Confined by FRP Material: a plasticity approach, Engineering Structures, Cilt. 24, s. 923-932. DOI: 10.1016/S0141-0296(02)00011-1