EN 1993 which verification formula to use stress or resistance? 3

[mohamed abdel aziz]

hello everyone
in eurocode EN1993 6.2 Resistance of cross-sections 6.2.1(5) it states that:
NOTE The verification according to (5) can be conservative as it excludes partial plastic stress
distribution, which is permitted in elastic design. Therefore it should only be performed where the
interaction of on the basis of resistances NRd , MRd , VRd cannot be performed.
the question is when is the interaction on basis of resistances cannot be performed?

 

[HTURKAK]

ENG. mohamed abdel aziz (Structural)(OP)


-As per Clause 6.2.1(4 and 5 ) you may verify the resistance of all cross-sections elastically. The proposed equation (in clause 6.2.1(5)) is the famous von Mises yield criterion , whereby the interaction of the local stresses should not exceed the yield stress .

-Pls look 6.2.3 thru 6.2.10 ( axial, bending , shear , Bending and shear, bending shear axial ..) if resistances of cross section ( NRd , MRd , VRd ) can be performed .

I hope my respond answers to your question.



Use it up, wear it out;
Make it do, or do without.

NEW ENGLAND MAXIM

 

[mohamed abdel aziz]

thanks HTURKAK I appreciate your help
but actually I was wondering what are the conditions under which the verifications from 6.2.3 to 6.2.10 cannot be performed
and I have to resort to VON MISES
thanks again

 

[MRob909]

The classic answer of 'it depends' applies here - I wouldn't say there is a defining criteria when to use each method so you will have to use your judgement on a project by project basis.

I frequently use both approaches, but tend to use design resistances for 'typical' structural frames, buildings, grillages, beams etc. This allows you to take account of partial plasticity in your design and would therefore allow a slightly more economical solution.

I will use the elastic verification for bespoke fabricated items such as machined plate profiles, brackets, lifting eyes etc. Where I do not want to account for the plasticity and where the scale does not lead to a more economical design.

 

[HTURKAK]

The verifications from 6.2.3 to 6.2.10 should be normally satisfactory for frame elements . I have used the subject formula for only plate elements .




Use it up, wear it out;
Make it do, or do without.

NEW ENGLAND MAXIM

 

[mohamed abdel aziz]

thanks a lot guys I appreciate it really