Table 11.

Stress–strain models of FRP-confined concrete.

Reference	Expression of stress–strain model	Model parameters
Lam and Teng [3]	$f_c=\{\begin{array}{c}{E}_c{\epsilon }_c-\frac{{\left(E_c-E_2\right)}^2}{4f_{co}^{\prime }}{\epsilon }_c^2,0\le {\epsilon }_c\le {\epsilon }_0\\ f_{co}^{\prime }+E_2{\epsilon }_c,{\epsilon }_0\le {\epsilon }_c\le {\epsilon }_{cu}\end{array}$	-
Harajli et al. [62]	$f_c=\{\begin{array}{c}{f}_{c1}\left[\frac{2{\epsilon }_c}{{\epsilon }_{c1}}-{\left(\frac{{\epsilon }_c}{{\epsilon }_{c1}}\right)}^2\right],0\le {\epsilon }_c\le {\epsilon }_{c1}\\ \sqrt{\left(k_0^2-k\right)}-k_0,{\epsilon }_{c1}\le {\epsilon }_c\le {\epsilon }_{cu}\end{array}$	$k_0=0.0031k_1{E}_{lf}-f_{co}$ $k_1=1.25{\left(\frac{f_l}{f_{co}}\right)}^{-0.5}$ $k={f_{co}}^2-0.0032k_1{E}_{lf}{f}_{co}\left(\frac{{\epsilon }_c}{{\epsilon }_{co}}+0.9\right)$
Youssef et al. [46]	$f_c=\{\begin{array}{c}{E}_c{\epsilon }_c\left[1-\frac{1}{n}\left(1-\frac{E_2}{E_c}\right){\left(\frac{{\epsilon }_c}{{\epsilon }_{c1}}\right)}^{n-1}\right],0\le {\epsilon }_c\le {\epsilon }_{c1},E_2>0\\ E_c{\epsilon }_c\left[1-\frac{1}{n}{\left(\frac{{\epsilon }_c}{{\epsilon }_{c1}}\right)}^{n-1}\right],0\le {\epsilon }_c\le {\epsilon }_{c1},E_2>0\\ f_{c1}+E_2\left({\epsilon }_c-{\epsilon }_{c1}\right),{\epsilon }_{c1}\le {\epsilon }_c\le {\epsilon }_{cu}\\ \end{array}$	$n=\{\begin{array}{c}\frac{\left(E_c-E_2\right){\epsilon }_{c1}}{E_c{\epsilon }_{c1}-f_{c1}},E_2>0\\ \frac{E_c{\epsilon }_{c1}}{E_c{\epsilon }_{c1}-f_{c1}},E_2<0\end{array}$
Teng et al. [9]	$f_c=\{\begin{array}{c}{E}_c{\epsilon }_c-\frac{{\left(E_c-E_2\right)}^2}{4f_{co}^{\prime }}{\epsilon }_c^2,0\le {\epsilon }_c\le {\epsilon }_0\\ f_{co}^{\prime }+E_2{\epsilon }_c,{\epsilon }_0\le {\epsilon }_c\le {\epsilon }_{cu},if{\rho }_k\ge 0.01\\ f_{co}^{\prime }-\frac{f_{co}^{\prime }-f_{cu}}{{\epsilon }_{cu}-{\epsilon }_{co}}\left({\epsilon }_c-{\epsilon }_{co}\right),{\epsilon }_0\le {\epsilon }_c\le {\epsilon }_{cu},if{\rho }_k\le 0.01\end{array}$
Wei and Wu [57]	$f_c=\{\begin{array}{c}{E}_c{\epsilon }_c+\frac{f_{c1}-E_c{\epsilon }_{c1}}{{{\epsilon }_{c1}}^2}{{\epsilon }_c}^2,0\le {\epsilon }_c\le {\epsilon }_{c1}\\ f_{c1}+E_2\left({\epsilon }_c-{\epsilon }_{c1}\right),{\epsilon }_{c1}\le {\epsilon }_c\le {\epsilon }_{cu}\end{array}$	$E_2=\frac{f_{cu}-f_{c1}}{{\epsilon }_{cu}-{\epsilon }_{c1}}$
Samaan et al. [59]	$f_c=\frac{\left(E_1-E_2\right){\epsilon }_c}{{\left\{1+{\left[\frac{\left(E_1-E_2\right){\epsilon }_c}{f_0}\right]}^n\right\}}^{\frac{1}{n}}}+E_2{\epsilon }_c$	$f_0=f_{cc}-E_2{\epsilon }_{cu}$; $n=1+{\left(\frac{E_1}{E_2}-1\right)}^{-1}$
Zhou and Wu [61]	$\sigma =\left[\left(E_1{\epsilon }_n-f_0\right)e^{-\frac{\epsilon }{{\epsilon }_n}}+f_0+E_2\epsilon \right]\left(1-e^{-\frac{\epsilon }{{\epsilon }_n}}\right)$	${\epsilon }_n=f_o/E_1$; $E_2=\frac{f_{cc}-f_o}{{\epsilon }_{cu}}$
Jiang and Teng [2]	$\frac{{\sigma }_c}{f_{cc}^{\prime *}}=\frac{\left({\epsilon }_c/{\epsilon }_{cc}^{*}\right)r}{r-1+{\left({\epsilon }_c/{\epsilon }_{cc}^{*}\right)}^r}$ $\begin{array}{c}\frac{{\epsilon }_c}{{\epsilon }_{co}}=0.85\left(1+8\frac{{\sigma }_l}{f_{co}^{\prime }}\right)\times {\{\left[1+0.75\left(\frac{-{\epsilon }_l}{{\epsilon }_{co}}\right)\right]}^{0.7}\hfill \\ \hfill -\exp \left[-7\left(\frac{-{\epsilon }_l}{{\epsilon }_{co}}\right)\right]\}\hfill \end{array}$	$r=\frac{E_c}{E_c-f_{cc}^{\prime *}/{\epsilon }_{cc}^{*}}$; $\frac{f_{cc}^{\prime *}}{f_{co}^{\prime }}=1+3.5\frac{{\sigma }_l}{f_{co}^{\prime }}$ $\frac{{\epsilon }_{cc}^{*}}{{\epsilon }_{co}}=1+17.5{\left(\frac{{\sigma }_l}{f_{co}^{\prime }}\right)}^{1.2}$; ${\sigma }_l=-\frac{2E_{frp}{t}_{frp}{\epsilon }_l}{D}$