Effect of corner radius and aspect ratio on compressive behavior of rectangular concrete columns confined with CFRP

Finite element analysis of axially loaded FRP-confined rectangular concrete columns

“…In summary, poor confinement effect in rectangular sections caused by non-uniform and anisotropic confining stresses will be alleviated by larger corner roundness and an aspect ratio closer to 1, and this phenomenon is even more obvious at post-yield stage. It should be noted that similar observations about the effect of corner roundness and aspect ratio on the behaviours of axially loaded FRP-confined rectangular concrete columns are also discussed in Mostofinejad et al's research [32] as well, while the current research is more comprehensive and detailed on the distribution of axial stress across the section. Although Dong et al's [18] axial strain-lateral strain relation, Menétrey and Willam's triaxial failure surface [21] and Attard and Setange's axial stress-strain relation [22] have been used in the constitutive modelling of concrete, it should be noted that each of these components adopted in the FE model can be replaced by other available alternatives to further enhance the performance of the FE procedure.…”

Simplified analytical models for compressed concrete columns confined by FRP and FRCM system

“…Most of these models are based on steel confinement, using the approach of Mander et al [23] to evaluate the ultimate strength of concrete subjected to compression under constant confinement with proper adjustments to overcome the initial hypothesis of constant lateral pressure exerted on concrete. Various confinement models have been calibrated on columns wrapped by FRP and FRCM fiber sheets [15,19,[24][25][26] that usually correlate the increase of strength and ultimate strain with the confinement lateral pressure applied by the fiber sheets. Some authors have proposed confinement models where the same mathematical form is adopted for both FRP and FRCM systems but different coefficients are used in the two cases (see e.g.…”

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

“…In order to maximize the confinement effect of the intermittent wrapping, the confinement generated by CFRP strips and steel ties (Barros and Ferreira, 2008;Triantafyllou, et al, 2015). The width of the CFRP strips was also chosen to be the same as the clear spacing based on the available experimental studies on intermittent wrapping (Barros and Ferreira, 2008;Colomb, et al, 2008;Hassan, et al, 2017;Mostofinejad, et al, 2015;Mostofinejad, 2016a, 2016b). Accordingly, the width and clear spacing of the CFRP strips for the specimens of Group SI were 40 mm, which were equal to half of the centre-to-centre spacing of the steel ties.…”

“…Rounding the sharp corners of square columns was proven to be an effective technique to increase the confinement effectiveness of full wrapping (Al-Salloum, 2007;Mostofinejad, Moshiri, & Mortazavi, 2015;Wang and Wu, 2008;Yang, et al, 2004). It was also reported that the increase in the corner radii was directly proportional to the strength gained of fully FRP wrapped square columns (Wang and Wu, 2008).…”