Table 6 Summary of FRP-confining models for fully wrapped circular sections.
Model | Concrete confined strength | Confining pressure | |
|---|---|---|---|
ACI 440.2R (2008) | \( f_{cc}^{'} = f_{c}^{'} + \psi_{f} 3.3f_{l} \) \( f_{cc}^{'} = f_{c}^{'} \) | if \( \frac{{f_{l} }}{{f_{c}^{'} }}\;\; \ge \;\;0.08 \) if \( \frac{{f_{l} }}{{f_{c}^{'} }}\;\; < \;\;0.08 \) | \( \psi_{f} = \;0.95 \) \( f_{l} = \frac{{2E_{f} nt_{f} \varepsilon_{fe} }}{D} \) \( \varepsilon_{fe} = 0.55\,\varepsilon_{fu} \) |
CNR (2013) | \( \frac{{f_{cc}^{'} }}{{f_{c}^{'} }} = 1\; + \;2.6\left( {\frac{{f_{l,eff} }}{{f_{c}^{'} }}} \right)^{2/3} \) \( \frac{{f_{cc}^{'} }}{{f_{c}^{'} }} = 1 \) | if \( \frac{{f_{l,eff} }}{{f_{c}^{'} }}\;\; > \;\;0.05 \) if \( \frac{{f_{l,eff} }}{{f_{c}^{'} }}\;\; \le \;\;0.05 \) | \( f_{l,eff} \;\; = \;\;\frac{{2E_{f} nt_{f} \varepsilon_{fd,rid} }}{D} \) \( \varepsilon_{fd,rid} = \;\;\hbox{min} \{ \eta_{a} \;\varepsilon_{fu} /\gamma_{f} ;\;0.004\} \) |
Lam and Teng (2003) | \( \frac{{f_{cc}^{'} }}{{f_{co}^{'} }} = \;\;1\,\; + \;3.3\frac{{f_{l,a} }}{{f_{co}^{'} }} \) \( \frac{{f_{cc}^{'} }}{{f_{co}^{'} }} = \;\;1 \) | if \( \frac{{f_{l,a} }}{{f_{co}^{'} }}\,\,\, \ge \,\;0.07 \) if \( \frac{{f_{l,a} }}{{f_{co}^{'} }}\;\; < \;\;0.07 \) | \( f_{l,a} \;\; = \;\;\frac{{2E_{f} t_{f} \varepsilon_{h,rup} }}{D} \) for CFRP, \( \varepsilon_{h,rup} = \;\,0.586\;{\kern 1pt} \varepsilon_{fu} \) for GFRP, \( \varepsilon_{h,rup} = \;\;0.624\;\varepsilon_{fu} \) |
Teng et al. (2009) | \( \frac{{f_{cc}^{'} }}{{f_{co}^{'} }}\;\; = \;\;1 + 3.5\left( {\rho_{k} - 0.01} \right)\rho_{\varepsilon } \) \( \frac{{f_{cc}^{'} }}{{f_{co}^{'} }}\;\; = \;\;1 \) | if \( \rho_{k} \;\; \ge \;\;0.01 \) if \( \rho_{k} \;\; < \;\;0.01 \) | \( \rho_{k} = \;\;\frac{{2E_{f} t_{f} }}{{\left( {f_{co}^{'} /\varepsilon_{co} } \right)D}} \) \( \rho_{\varepsilon } = \;\;\frac{{\varepsilon_{h,rup} }}{{\varepsilon_{co} }} \), \( \varepsilon_{co} = \;\;0.002 \) |
Wu and Wang (2009) | \( \frac{{f_{cc}^{'} }}{{f_{co}^{'} }} = 1\; + \;2.23\left( {\frac{{f_{lu} }}{{f_{co}^{'} }}} \right)^{0.96} \) | Â | \( f_{lu} = \;\;\frac{{2f_{f} nt_{f} }}{D} \) |
Fahmy and Wu (2010) | \( f_{cc}^{'} = f_{co}^{'} \; + \;k_{1} f_{lu} \) \( k_{1} = 4.5f_{lu}^{ - 0.3} \) if \( f_{co}^{'} \;\; \le \;\;40{\kern 1pt} \;{\text{MPa}} \) \( k_{1} = 3.75f_{lu}^{ - 0.3} \) if \( f_{co}^{'} > \;40{\kern 1pt} \;{\text{MPa}} \) | Â | \( f_{lu} = \frac{{2f_{f} nt_{f} }}{D} \) |
Ozbakkaloglu and Lim (2013) | \( f_{cc}^{'} = c_{1} f_{co}^{'} + 3.2\,\left( {f_{l,a} - f_{lo} } \right) \) \( c_{1} = 1 + 0.0058\frac{{E_{l} }}{{f_{co}^{'} }} \) \( f_{lo} = E_{l} \varepsilon_{l1} \) | Â | \( \varepsilon_{l1} = \;\;\left( {0.43 + 0.009\frac{{E_{l} }}{{f_{co}^{'} }}} \right)\,\varepsilon_{co} \) and \( E_{l} \,\ge \,f_{co}^{'\;1.65} \) |
Pham and Hadi (2014) | \( f_{cc}^{'} = 0.91f_{co}^{'} + 1.88f_{l} + 7.6\frac{{t_{f} }}{D} \) | Â | \( f_{l} = \frac{{2E_{f} nt_{f} \varepsilon_{fu} }}{D} \) |