ANGLES IN BENDING TO BS5950-1:2000 1

[SARAHJONES]

Having been brought up on BS449, I recently had to design angles to BS5950-1:2000 and found the whole process very complicated! Does anyone have an example of a calculation, particularly for UEs? Although the blue book gives various parameters for appendix B.2.9, it does not give them all. I'd like a shortcut, rather than working all the properties out from first principles!

 

[pba]

Are UE's unequal angles? What parameters can't you get from the published data? I've never had to design angles to the latest version of the code but I used to have a spreadsheet for the old version which simply contained all of those little subformulas and formulas (seven listed in BS5950-2000). This saved time in the calculation but was still presented as a 'hand calculation'. I've no longer got the spreadsheet.

This principle applies to a lot of BS5950 design and is especially useful for the appendices where they hide all the complicated stuff!

Good luck its not really that bad a code to work to.

 

[SARAHJONES]

Thanks for that. I do use BS5950 on a daily basis, but hadn't designed an angle in bending for a while! I am writing a spreadsheet, but wanted to know if there were any published data for Zuu, Zvv etc.

Just to check the method:
1)Cl 4.3.8.2 - resolve Mx into Mu and Mv
2)B.2.9 - calc lambda LT.
3) 4.9 to I.4 - does this mean use all values for u and v axes? If so pcu is based on Le/ru etc and Zu and Zv, mu and my etc to be used. BUT what do I use for Mb? Is it just pbZu?
Some UEs are slender, but presumably I have use I.3 rather than Mb = pbZueff?

As I said, it's complicated! But if my above method is correct I will finish the spreadsheet and send it to anyone interested (with all the ususal caviats).

 

[EIT2]

What is BS5950?

Thank you!

 

[Kapitan]

EIT2, in the UK these are British Standards.

From GOOGLE search for British Standard 5950,
[blue]
BS 5950-1: 2000 - Structural use of steelwork in
building. Code of practice for design - Rolled and
welded sections.
[/blue]

 

[pba]

Sarah. - Yes I think your approach is correct - My annotations are below

1)Cl 4.3.8.2 - resolve Mx into Mu and Mv - note that My (if present) also needs resolving to Mu and Mv.
2)B.2.9 - calc lambda LT. - Agreed
3) 4.9 to I.4 - does this mean use all values for u and v axes? If so pcu is based on Le/ru etc and Zu and Zv, mu and my etc to be used. BUT what do I use for Mb? Is it just pbZu? - Yes thats my understanding, You design the section replacing #x terms with #u and #y with #v. I would take it that the absence of Su and Sv terms from the data indicates that Zu and Zv should be used.
Some UEs are slender, but presumably I have use I.3 rather than Mb = pbZueff?- This one I don't know - try not to use slender angles?!?

Again, good luck

 

[linslade]

The 'new' section properties for angles can be found in BS EN 10056-1:1999. Specification for Structural Steelwork Equal and Unequal Angles. I believe that this was the old BS 4.

Regards