HK SDM

The density of normal weight concrete is assumed to be 2400 kg/m³.

The design strength is given in 5.3.2.1(b) of BS 5400-4 by

$$f_{cd}=0.6 f_c / \gamma \\$$

The tensile strength is given in 6.3.4.2 as

$$f_{ct}=0.36 \sqrt{f_c} \\$$

but from BS5400 a value of 1MPa should be used at the position of tensile reinforcement.

The elastic modulus is tabulated in Table 21.

$f_c$ (MPa)	$E$ (GPa)
20	18.9
25	20.2
32	21.7
40	24.0
45	26.0
50	27.4
55	28.8
60	30.2

The strains are defined as:

	$\varepsilon_{cu}$	$\varepsilon_{ax}$	$\varepsilon_{plas}$	$\varepsilon_{max}$	$\varepsilon_{peak}$
Parabola-rectangle	0.0035	$\varepsilon_{cu}$	$\varepsilon_{RP}$
Rectangle
Bilinear
Linear				0.0035	$\varepsilon_{max}$
Non-linear
Popovics
EC2 Confined
AISC filled tube
Explicit	0.0035	$\varepsilon_{cu}$		0.0035

$$\varepsilon_{RP}=2.4 \times 10^{-4} \sqrt{\frac{f_c}{\gamma}} \\$$

See also the Theory section on Concrete material models.