VII Div3 2008a - Article KD-2 discussion

[FC2008]

Hi,
I'm comparing the basic design requirements from 2004 with 2008 and have found some changes which I do not completely understand.

KD-240 Elastic-Plastic Analysis from 2004:

b) A design margin of a t least 1.732 shall be applied to the load that causes the strain to exceed 5% at any point in the structure.

KD-230 Elastic-Plastic Analysis from 2008:

b) A design margin of at least 1.732 shall be applied to the load that causes the total accumulated damage at any point in the structure, D_epsilon_t to exceed 1.0 considering all loadings that will be applied to the component and all of the load step increments in the analysis in accordance with the following procedure:

1) change in total equvalent plastic strain
2) limiting triaxial strain for the k^th load step using given equation.
3) Strain limit damage for the k^th load step increment using equation.

I won't try to write the equation given.

If someone could please explain these steps to me, or point me to a place where they are discussed I would greatly appreciate it.