IPE 450 for a span of 18m?! 1

[ITV]

Dear friends,
i have a span of 18m. (see image below).
The purlins are in a 1,5 distance carrying a load of 2,2kN/m each.

I analysed the system using my software. A HEA 400 seems to be enough. But...i am new, i would think more reasonable a IPE450-500, and would like your thoughts/suggestions.





Architects don't want a beam higher than 400mm for their reasons. Because there is not a lot of free height under the roof

 

[wth]

Do your software account for lateral buckling? Without running the numbers, HEA400 seems optimistic for 18 m, and IPE450/500 will probably almost be equal to the HEA in strength.

 

[XR250]

I can't imagine LTB being an issue with 1.5m brace spacing. Honestly, if you are new, maybe do this by hand instead of relying on software. Deflection will likely control this design. What did the software come up with?

 

[ITV]

I think the same! That's why my head exploded! I would imagine a bigger HEA or HEB or IPE or..even HEM. I will check deflection too, yes

 

[ITV]

Yes, an IPE 450 seems ok according to the software. XD sorry for asking your opinion guys, thank you!
If i could, i would use a truss, but its not possible due to architectural reasons

 

[JLNJ]

If your columns are modeled to resist thrust from your beam, then the deflection modeled won't be accurate. Make sure that the model matches the real world behavior.

Additionally, the fact that it's a bent beam makes the splice connection very important. Any flexibility at the splice also increases the deflection.