RSA Steel Design BS EN 1993-1-1 Mz not being considered in stability check

[richard_russell]

Dear RSA team,

I'm having difficult with the steel design module within RSA.  I have two identical member with very similar internal forces (members 9 & 34), when I carry out the steel design with my own calculated Mcr value one of the members (9) includes the Mz value for the load combination (combination 56) and the other member doesn't (34).  I only picked this up as member 9 was failing but could see adjacent similar members were not.  In my opinion member 9 is correct, I have created a member type (406UB) assigned to all the same members.  

Furthermore, I've tried to exlude negative (hogging) moments from the design using the 'exclude internal forces from calculation' option within the configuration but no matter what stress type of combination I use min/max +/- values it doesnt exclude anything.  I have read the help sections on this but can't get it to work, my stress for these members are all under 300Mpa.

I have attached the substructure model for the area in question and left the view point open at the location of the issues.  Could you please advise what may be happening?

Thanks 

Richard

[richard_russell]

Posted without model attached as I was unable to add the model dye to 'file extension not matching' please let me know how I should upload the model to you.  Thanks

[Simau]

@richard_russell 

Zip it before

[richard_russell]

Thanks! Also, I think I'm getting the difference because member 34 has a tiny amount of tension, I'm not aware that this tension would negate the need for a biaxial check?

[Simau]

Hi @richard_russell 

According to what i understood with your substructure, i should assign this member type to these beams:

It's better if you split member 9 and 34 in 2 parts and design them again with a specific member type