Behavior of partially and fully FRP-confined circularized square columns under axial compression

Performance evaluation of intermittently CFRP wrapped square and circularised square reinforced concrete columns under different loading conditions

“…Cracking of the concrete cover started at the non-wrapped region around the mid-height then propagated to the two ends of Specimens SI-0 and CI-0. Similar observations of cracking of the concrete cover in the non-wrapped region were also reported in previous research studies (Matthys, Toutanji, Audenaert, & Taerwe, 2005;Saljoughian and Mostofinejad, 2016b;Zeng, et al, 2017). Afterwards, Specimens SI-0 and CI-0 experienced the rupture of the CFRP strip around the mid-height of the specimens, which was followed by crushing of the concrete and buckling of the longitudinal steel bars.…”

“…It is noted that most of the RC building columns in practice have square or rectangular cross-section (Kim, Yi, Lee, Park, & Kim, 2003;Tao, et al, 2008). For strengthening deficient square columns, intermittent wrapping could be an efficient and effective solution if the columns require a moderate improvement in the strength and ductility (Zeng, Guo, Gao, Li, & Xie, 2017). Several studies investigated the behaviour of intermittently 2014; Triantafyllou, et al, 2015;Zeng, et al, 2017).…”

“…For strengthening deficient square columns, intermittent wrapping could be an efficient and effective solution if the columns require a moderate improvement in the strength and ductility (Zeng, Guo, Gao, Li, & Xie, 2017). Several studies investigated the behaviour of intermittently 2014; Triantafyllou, et al, 2015;Zeng, et al, 2017). It was found that intermittent wrapping improved the strength and ductility of square columns (Hodhod, et al, 2005;Maaddawy, 2009;Triantafyllou, et al, 2015).…”

“…In Priestley, et al (1994), rectangular columns were bonded with precast concrete bolsters to obtain elliptical columns. Thereafter, the performance of FRP wrapped circularized square columns (square cross-section modified to circular cross-section) was investigated in several research studies Hadi, Pham, & Lei, 2013;Kim, et al, 2003;Pham, Doan, & Hadi, 2013;Youssf, Hassanli, & Mills, 2017;Zeng, et al, 2017). It was reported that the circularization led to a substantial improvement in the strength and ductility of the columns due to the elimination of the stress-concentration at the corners.…”

“…It was reported that the circularization led to a substantial improvement in the strength and ductility of the columns due to the elimination of the stress-concentration at the corners. However, most of the available studies investigated the performance of circularized square concrete cylinders (Jameel, et al, 2017;Kim, et al, 2003;Youssf, et al, 2017), circularized square columns (columns without steel reinforcement) (Zeng, et al, 2017) or circularized square RC columns (Hadi, et al, 2017;Hadi, et al, 2013; with full wrapping. Only one study investigated the performance of circularized square columns (columns without steel reinforcement) (Zeng, et al, 2017) with intermittent wrapping in which the columns were subjected to only concentric axial loads.…”