Table 4 Failure criterion and damage index (Kim et al. 2007).

Concrete

Compressive and shear

$0.004+\frac{1.4{\mathit{\rho }}_s{f}_{\mathit{yh}}{\mathit{\epsilon }}_{\mathit{sm}}}{f_{\mathit{cc}}^{\prime }}$

$1-{\mathit{ftg}}_c{(\frac{2{\mathit{\epsilon }}_{\mathit{cu}}-{\mathit{\epsilon }}_{\mathit{cs}}}{2{\mathit{\epsilon }}_{\mathit{cu}}})}^2$

Steel

Tensile

$1.20{(\frac{{\mathit{\epsilon }}_{\mathit{ts}}}{2{\mathit{ftg}}_r{\mathit{\epsilon }}_{\mathit{tu}}})}^{0.67}$