Effect of CFRP location on flexural and axial behavior of SHS steel columns strengthened using CFRP

Document Type : Original Article

Author

Assistant professor, Department of Civil Engineering, Zahedan Branch, Islamic Azad University, Zahedan, Iran

Abstract

In recent years, the use of Carbon Fiber Reinforced Polymers (CFRP) for strengthening and retrofitting of steel structures has been considerably developed. Strengthening and retrofitting of structures have several reasons, including: design and calculation errors, lack of proper construction techniques, change in application after construction, damage caused by natural disasters such as floods and earthquakes, the occurring of fatigue cracking, metals corrosion, and so on. The column is an important member in building structures that has the duty to bear and transferring loads incurred to the structure. The stability in structural steel columns is very important. According to research conducted in literature, a few studies have done on the axial behavior of slender steel columns strengthened using carbon fiber reinforced composite. However, the main purpose of this study is to analyze the ultimate load of compressive and compressive-flexural (interaction loads) of square hollow section steel columns strengthened using composite carbon fiber with CFRP in different locations. For modeling and analysis of samples ANSYS software was used. 40 steel columns that strengthened using CFRP were analyzed by nonlinear static under axial compressive load. Three samples of the columns were also analyzed under compressive axial load and flexural moment interaction. The results showed that location, coverage percent and number of layers of CFRP are effective on the ultimate load of SHS steel columns under axial compression load and flexural moment. The results also showed that moving the location of the carbon composite with percentage of defined coverage can be have different effects on the axial compression load of steel columns.

Keywords

Main Subjects


[1] ACI Committee 440, (2002). Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures. ACI440.2R-02, Farmington Hills, MI, American Institute.
[2] Teng, J. G., Hu, Y. M. (2007). Behavior of FRP jacketed circular steel tubes and cylindrical shells under compression. International Journal of Construction and Building Materials, 21, 827–838.
[3] Kalavagunta, S., Naganathan, S., Bin Mustapha K. N. (2013). Proposal for design rules of axially loaded CFRP strengthened cold formed lipped channel steel sections. Thin-Walled Structures, 72, 1-14.
[4] Jiao, H., Zhao, X. L. (2004). CFRP strengthened butt-welded very high strength (VHS) circular steel tubes. Thin-Walled Structures, 42(7), 963–78.
[5] Tao, Z., Han, L. H., Wang, L. L. (2007). Compressive and flexural behavior of CFRP-repaired concrete-filled steel tubes after exposure to fire. Journal of Constructional Steel Research, 63, 1116–1126.
[6] Kalavagunta, S., Naganathan, S., Bin Mustapha K. N. (2013). Proposal for design rules of axially loaded CFRP strengthened cold formed lipped channel steel sections. Thin-Walled Structures, 72, 1-14.
[7] Gao, X. Y., Balendra, T., Koh, C. G. (2013). Buckling strength of slender circular tubular steel braces strengthened by CFRP. Engineering structures, 46, 547-556.
[8] Shaat, A., Fam, A. (2006). Axial loading tests on CFRP-retrofitted short and long HSS steel columns. Canadian Journal of Civil Engineering, 33(4), 458–70.
[9] Haedir, J., Zhao, X. L. (2011). Design of short CFRP-reinforced steel tubular columns. Journal of Constructional Steel Research, 67, 497–509.
[10] Bambach, M. R., Elchalakani, M. (2007). Plastic mechanism analysis of steel SHS strengthened with CFRP under large axial deformation. Thin-Walled Structures, 45, 159–170.
[11] Sundarraja, M. C., Sivasankar, S. (2013). Experimental investigation on FRP confined HSS tubular members under compression. Journal of structural Engineering, 40, 298-304.
[12] Sundarraja, M. C., Ganesh Prabhu, G. (2012). Experimental study on CFST members strengthened by CFRP composites under compression. Journal of Constructional Steel Research, 72, 75-83.
[13] Tao, Z., Han, L. H., Wang, L. L. (2007). Compressive and flexural behavior of CFRP-repaired concrete-filled steel tubes after exposure to fire. Journal of Constructional Steel Research, 63, 1116–1126.
[14] Feng, P., Zhang, Y., Bai, Y., Ye, L. (2013). Strengthening of steel members in compression by mortar-filled FRP tubes. Thin-Walled Structures, 64, 1–12.
[15] Keykha, A. H., Nekooei, M. and Rahgozar, R. (2015). Experimental and theoretical analysis of hollow steel columns strengthening by CFRP. Civil Engineering Dimension, 17 (2), 101-107. 
[16] Keykha, A. H., Nekooei, M., Rahgozar, R. (2016). Numerical and experimental investigation of hollow steel columns strengthened with carbon fiber reinforced polymer. Journal of Structural and Construction Engineering, 3 (1), 49-58.
[17] Keykha, A. H., Nekooei, M. and Rahgozar, R. (2016). ANALYSIS AND STRENGTHENING OF SHS STEEL COLUMNS USING CFRP COMPOSITE MATERIALS. Composites: Mechanics, Computations, Applications. An International Journal, 7 (4), 275–290.