IRC 112

The density of normal eight concrete is assumed to be 2200 kg/m³.

The design strength is given in 6.4.2.8

$$f_{cd}=0.67 f_c/ \gamma \\$$

In A2.9(2) the strength is modified for the rectangular stress block to

$$f_{cd}=0.67 f_c/ \gamma \space \space \space \space \space \space \space \space \space \space f_c \leq 60MPa \\ f_{cd}=0.67(1.24- f_c/250)f_c/ \gamma \space \space \space \space \space \space \space \space \space f_c > 60MPa \\$$

The tensile strength is given in by A2.2(2) by

$$f_{ct}=0.259 f_c^{2/3} \space \space \space \space \space \space \space \space \space \space f_c \leq 60MPa \\ f_{ct}=2.27ln(1+(f_c+10)/12.5) \space \space \space \space \space \space f_c > 60MPa \\$$

The elastic modulus is given in A2.3, equation A2-5

$$E=22 \Bigl (\frac{f_c+10}{12.5} \Bigl )^{0.3}\\$$

The strains are defined as

	$\varepsilon_{cu}$	$\varepsilon_{ax}$	$\varepsilon_{plas}$	$\varepsilon_{max}$	$\varepsilon_{peak}$
Parabola-rectangle	$\varepsilon_{cu2}$	$\varepsilon_{c2}$	$\varepsilon_{c2}$	$\varepsilon_{cu2}$	$\varepsilon_{c2}$
Rectangle	$\varepsilon_{cu3}$	$\varepsilon_{c3}$	$\varepsilon_{\beta}$
Bilinear	$\varepsilon_{cu3}$	$\varepsilon_{c3}$	$\varepsilon_{c3}$	$\varepsilon_{cu3}$	$\varepsilon_{c3}$
Linear				$\varepsilon_{cu2}$	$\varepsilon_{c2}$
Non-linear				$\varepsilon_{cu1}$	$\varepsilon_{c1}$
Popovics
EC2 Confined	$\varepsilon_{cu2,c}$	$\varepsilon_{c2,c}$	$\varepsilon_{c2,c}$
AISC filled tube
Explicit	$\varepsilon_{cu2}$	$\varepsilon_{cu2}$		$\varepsilon_{cu2}$

$$\varepsilon_{c1}=0.00653 (f_c+10)^{0.31} \space \space \space \space \leq 0.0028 \\$$ $$\varepsilon_{cu1}= \begin{cases} 0.0035 \space \space \space \space \space \space \space f_c \leq 60MPa \\ 0.0028+0.027 \Bigl (\frac{90-0.8 f_c}{100} \Bigl )^4 \\ \end{cases}$$ $$\varepsilon_{c2}= \begin{cases} 0.002 \space \space \space \space \space \space \space \space \space \space \space f_c \leq 60MPa \\ 0.002+0.000085(0.8 f_{ck}-50)^{0.53} \\ \end{cases}$$ $$\varepsilon_{cu2}= \begin{cases} 0.0035 \space \space \space \space f_c \leq 60MPa \\ 0.0026+0.035 \Bigl (\frac{90-0.8 f_c}{100} \Bigl )^4 \\ \end{cases}$$ $$\varepsilon_{c3}= \begin{cases} 0.00175 \space \space \space \space f_c \leq 60MPa \\ 0.00175+0.00055 \Bigl (\frac{0.8 f_{ck}-50}{40} \Bigl ) \\ \end{cases}$$ $$\varepsilon_{cu3}= \begin{cases} 0.0035 \space \space \space \space f_c > 50MPa \\ 0.0026+0.035 \Bigl (\frac{90-0.8 f_c}{100} \Bigl )^4 \\ \end{cases}$$

See also the Theory section on Concrete material models.