Numerical Investigation on Structural Behaviors of Deficient Steel CHS Long Columns Strengthened Using CFRP

Document Type : Research Article

Author

Department of Civil Engineering, Nikshahr Branch, Islamic Azad University, Nikshahr, Iran

Abstract

Structures often suffer damage due to various factors, including accidental loads, corrosion, and reduced strength, necessitating the need for repairs. The use of Carbon Fiber Reinforced Polymer (CFRP) to strengthen steel members has gained considerable attention in recent decades. However, most previous research has focused on studying the behavior of non-deficient steel structures. This study aims to investigate long steel circular columns with primary defects in vertical and horizontal notches, and examine the effects of CFRP retrofitting. A total of fifteen specimens of steel long Circular Hollow Section (CHS) columns, each with the same height but varying damage dimensions, were analyzed using ABAQUS 2016 software under compressive load. The main challenge with long columns is global buckling under compressive loads. To improve the accuracy of the analysis, a combined method was employed to study the post-buckling behavior of the plastic zone. Specifically, the specimens underwent elastic buckling analysis followed by RIKS non-linear analysis considering both general and local imperfections. The results showed that defects in the steel columns reduced the load-bearing capacity by up to 52%. Horizontal defects had a greater impact on reducing the ultimate load compared to vertical damage (up to 13%). Additionally, deficiencies significantly affected the buckling of the defect area, resulting in axial deformation. CFRP retrofitting strengthened the columns, increasing the ultimate load capacity (up to 51%), delaying defect buckling, controlling fractures, and reducing stresses in the damaged zone.

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[1] Y. Chen, J. Wan, K. He, Experimental investigation on axial compressive strength of lateral impact damaged short steel columns repaired with CFRP sheets, Thin-Walled Structures, 131 (2018) 531-546.
[2] C. Huang, T. Chen, X. Wang, Compressive characteristics of damaged circular hollow section (CHS) steel columns repaired by CFRP or grout jacketing, Thin-Walled Structures, 119 (2017) 635-645.
[3] A. Cinitha, P.K. Umesha, N.R. Iyer, An overview of corrosion and experimental studies on corroded mild steel compression members, KSCE Journal of Civil Engineering, 18(6) (2014) 1735-1744.
[4] S. Sandrasekaran, T. Thilakranjith, M. Sundarraja, Axial behavior of CFRP jacketed HSS tubular members-an experimental investigation, 5 (2012) 1729-1737.
[5] Q.-L. Wang, Z. Zhao, Y.-B. Shao, Q.-L. Li, Static behavior of axially compressed square concrete filled CFRP-steel tubular (S-CF-CFRP-ST) columns with moderate slenderness, Thin-Walled Structures, 110 (2017) 106-122.
[6] K. Karimi, W.W. El-Dakhakhni, M.J. Tait, Behavior of Slender Steel-Concrete Composite Columns Wrapped with FRP Jackets, 26(5) (2012) 590-599.
[7] M. Touhari, R. Mitiche-Kettab, Behaviour of FRP Confined Concrete Cylinders: Experimental Investigation and Strength Model, Periodica Polytechnica Civil Engineering, 60(4) (2016) 647-660.
[8] G. Pachideh, M. Gholhaki, Evaluation of Concrete Filled Steel Tube Column Confined with FRP, 2 (2019) 2019.
[9] G. Pachideh, M. Gholhaki, A. Moshtagh, An Experimental Study on Cyclic Performance of the Geometrically Prismatic Concrete-Filled Double Skin Steel Tubular (CFDST) Columns, Iranian Journal of Science and Technology, Transactions of Civil Engineering, 45(2) (2021) 629-638.
[10] G. Pachideh, M. Gholhaki, A.J.J.o.T. Moshtagh, Evaluation, Impact of temperature rise on the seismic performance of concrete-filled double skin steel columns with prismatic geometry, 49(4) (2021) 2800-2815.
[11] S. Kalavagunta, S. Naganathan, K.N. Bin Mustapha, Proposal for design rules of axially loaded CFRP strengthened cold formed lipped channel steel sections, Thin-Walled Structures, 72 (2013) 14-19.
[12] M. Sundarraja, S. Sandrasekaran, Behaviour of CFRP jacketed HSS tubular members under compression - An experimental investigation, 39 (2012) 574-582.
 [13] G. Ganesh Prabhu, M.C. Sundarraja, Behaviour of concrete filled steel tubular (CFST) short columns externally reinforced using CFRP strips composite, Construction and Building Materials, 47 (2013) 1362-1371.
[14] J.F. Dong, Q.Y. Wang, Z.W. Guan, Structural behaviour of recycled aggregate concrete filled steel tube columns strengthened by CFRP, Engineering Structures, 48 (2013) 532-542.
[15] O. Yousefi, K. Narmashiri, M. Ghaemdoust, Structural behaviors of notched steel beams strengthened using CFRP strips, Steel and Composite Structures, 25 (2017) 35-43.
[16] M.R. Ghaemdoust, K. Narmashiri, O. Yousefi, Structural behaviors of deficient steel SHS short columns strengthened using CFRP, Construction and Building Materials, 126 (2016) 1002-1011.
[17] M. Karimian, K. Narmashiri, M. Shahraki, O. Yousefi, Structural behaviors of deficient steel CHS short columns strengthened using CFRP, Journal of Constructional Steel Research, 138 (2017) 555-564.
[18] C. Buchanan, E. Real, L. Gardner, Testing, simulation and design of cold-formed stainless steel CHS columns, Thin-Walled Structures, 130 (2018) 297-312.
[19] Sika Warp -230 C. Product Data Sheet.Edition13/06/2006.
[20] Sika, Sikadur®-330 Product Data Sheet [computer program]://irn.sika.com/en/solutions_products/construction-markets/sika-structural-strengthening-solutions/02a013/ 02a013sa09.html
[21] O. Zhao, L. Gardner, B. Young, Structural performance of stainless steel circular hollow sections under combined axial load and bending – Part 1: Experiments and numerical modelling, Thin-Walled Structures, 101 (2016) 231-239.
[22] Y. Huang, B. Young, Experimental investigation of cold-formed lean duplex stainless steel beam-columns, Thin-Walled Structures, 76 (2014) 105-117.
[23] O. Zhao, B. Rossi, L. Gardner, B. Young, Behaviour of structural stainless steel cross-sections under combined loading – Part I: Experimental study, Engineering Structures, 89 (2015) 236-246.