The purpose of the Column for Isolated Frame project is to perform buckling calculations of a concrete column as part of an isolated frame.

One of the factors which have influence on the buckling behavior of a column is the shape of the acting moments diagram. According to NEN-EN 1992-1-1 #5.8.8.2 the design moment value can be taken as sum of 1st and 2nd order moments. The original EN1992-1-1 formula is extended with the additional rule:

M_{Ed}=M_{0Ed}+M_{2}=Max(M_{0e}+M_{2}; M_{2}; M_{01}+0.5M_{2})

In the user interface for internal forces definition input fields group "Loads" is created. One of these fields is for defining of the axial force value N_{c;Ed}. The value can be negative (compression) or positive (tension).

Bending moment values at the ends of a column (M_{01}; M_{02}), at the middle point of a column (Mmid) and the maximum value of the bending moment (M_{yMax}; M_{zMax}) can be provided for both buckling axes Y and Z:

Loads of a column for an isolated frame:

If the value of M_{y(z)Max} will be zero, M_{0e} will be calculated according to the equation (5.32) depending on provided M_{y(z)01} and M_{y(z)02} values and for the nominal 2nd order moment calculations will be used factor c = 8.

If the end moments M_{y(z)01} and M_{y(z)02} values will be set to zero, the 1st order moment M_{0Ed} will be equal to the value provided for the maximum bending moment M_{y(z)Max} and for the nominal 2nd order moment calculations will be used factor c = 9,6.

For the other cases the 1st order moment M_{0Ed} will be set to a maximum from M_{y(z)02} and M_{y(z)Max} and for nominal 2nd order moment calculations will be used factor c = π^{2}.

The nominal second order moment is calculated according to the formula (5.33).