RAM Concept Help

Concrete Behavior

You define the concrete elastic modulus in the materials window. You can choose to use code equation 3.1.2 or a specified value.

When you directly specify values, there must be two elastic modulus values:
  • Eci = value for initial service (transfer) cross section analyses
  • Ec = value for all other conditions
When the AS 3600-2009 code section is selected the following values are used:
E c i = ρ 1.5 0.043 f c m i when f c m i 40 MPa ρ 1.5 0.024 f c m i + 0.12 when f c m i > 40 MPa
where
fcmi
=
mean value of cylinder strength at stressing. Determined using Table 3.1.2.
fcm
=
mean value of 28 day cylinder strength

For calculations based on the gross section, concrete is assumed to be a perfectly linear-elastic material with no stress or strain limits.

See Concrete Stress-Strain Curves for a description of the stress-strain curves used in a detailed cross section analysis.

The strength stress-strain curves are truncated at a strain of 0.003. The other stress-strain curves have no limit strain.