Potential discrepancy in design of Beam column between CiSC and CAN/CSA-S6-06

[HanStrulo]

Hi everyone.

I am designing a beam column according to CiSC and while i was doing so, I was referring a calculation done by one of clients for the design of the same beam column (W610X155).

It's under combined axial and bending stresses.

My approach is to always check the limitations present in Table 1, if the flange and web meets them, great, if it doesn't, I reduce the Fy until it does and I use the new Fy to determine the Cr of the beam column.

I check the class in bending and I determine the Mr accordingly (with the original Fy) and then i do the 3 combined checks in clause 13.8.2 or 13.8.3.

For this beam column (W610x155), I always end up reducing Fy from 345 MPA to 220 MPa for the calculation of Cr which penalizes it alot.

Today, while checking the client's calculations, I noticed that it doesn't do the checks in table one and uses the full Cr capacity since the start. For bending, it references clauses 10.10 of the CAN/CSA-S6-06.

Is there something fundamentally different between CiSC and the CAN/CSA-S6-06?
Am I doing unnecessary reduction of Cr?

Sorry for the long post. Any help is appreciated.

Thank you guys

 

[KootK]

Is there something fundamentally different between CiSC and the CAN/CSA-S6-06?

There shouldn't be given that CISC is basically just commentary over CSA.

Am I doing unnecessary reduction of Cr?

I suspect so. I don't think there should ever be a reduction applied to Cr. Either you meet the [Table 1] limits and you have no reduction, or you don't and you can't use that cross section as an axially loaded member.

Note that I've expanded upon these ideas a good deal in your other thread on this topic.

 

[jayrod12]

Isn't CSA S6-06 a bridge code?

Why would it apply to this beam column? If you're designing a bridge, then use S6, if a building S16. Don't mix design standards just because one may be more beneficial.

 

[KootK]

Isn't CSA S6-06 a bridge code?

So it is, missed that.

 

[HanStrulo]

Yes. I just realized that i was doing unnecessary reductions.

Basically i was always checking the beam columns as columns which is not helpful especially since i was using slender W section not suitable for pure axial load.

I did check both codes and they are saying the same fundamental things. I was just confused.

For anyone still confused by me using different codes, the beam is neither building or a bridge, it's excavation support that is near a highway and the bridge code is usually referenced in these cases for loading and checking.