HSS Column Selection for 4 Story Structural Steel Building

[KirkGH]

I've been tasked with designing columns for a 4 story building (interior columns only, the perimeter is concrete tilt wall).
Story Height: 15 feet
Floor: Vulcraft VLI composite slab/metal deck with open web steel joists and wide flange steel beams.
Roof: Metal Deck
Column Shape: Square HSS
Approximate 250 feet x 140 feet and 27 feet bays.
Column loads (unfactored/unreduced) up to 600 kips.

Question: In general, what do I need to keep in mind when selecting the sizes and specifying changes in sizes?
What's easiest to build?
Pointers in general?
What are good references? I looked on Google and sifted through the AISC design guides with no luck.

Thanks.

KGH

 

[SteelPE]

Are you required to use HSS sections for columns? With columns at 4x15=60' tall I would think a splice would be required. I find WF slightly easier to splice and the column connections tend to be a little easier to do with WF vs HSS (my opinion).

 

[dik]

Your connection costs with W sections would be considerably less...

Dik

 

[KirkGH]

The HSS criteria came from the engineer above me. Ease of tying in cold formed steel studs and cleaner connection details around an HSS is one reason, architect preference another. The project started with W columns and has switched. Not sure on the exact reason why but I'll get clarification.

Quick research showed columns should be no more than 3 stories, so if splices are expensive it may be good to go with one splice only, at 3rd floor. ?Makes it about a 32 foot column which I imagine can be easily transported.

KGH

 

[dik]

The real cost will be the structural steel metalwork... not the framing for the steel studs.

 

[SteelPE]

Usually HSS are smaller in terms of weight as you tend to get more r/pound than you do with a WF. However last I heard (and it was a while ago) they are more expensive/pound too. When you add a splice into the mix it becomes a little more complicated.

 

[ameyerrenke]

If you only need the column 45', why splice it? Even at 32' it'll need to ship on a 45' or 48' foot flatbed. If its shipping on a 45'+ flatbed there's no reason you can't use the whole bed length (Assuming there aren't any other constraints). Everyone has their preferences, but mine would be not to splice unless necessary.

 

[PUEngineer]

I'm of the opinion that if the OPer has a justifiable reason and the architect/owner is okay with the choice, or even pushing that choice, then it's an acceptable choice. It's not like it's impossible or a whole other bag of complicated. I used to work for a smaller firm that worked on similar type projects and tube columns were all they used; typical details and design standards were setup accordingly.

I would think there are several design guides from AISC that might be somewhat beneficial; 5, 7 (maybe), 22, 23 and 24.

 

[SteelPE]

ameyerrenke, I am under the impression that the column is 4 x 15' = 60' tall. Would you still not splice this column?

PU, I agree if there is a requirement from the owner or architect that tubes should be used, but if a tube is being used strictly because it weighs less then that economy may be untrue due to other factors.

 

[ameyerrenke]

KirkGH (Structural)
4 Feb 14 9:16
The HSS criteria came from the engineer above me. Ease of tying in cold formed steel studs and cleaner connection details around an HSS is one reason, architect preference another. The project started with W columns and has switched. Not sure on the exact reason why but I'll get clarification.

Quick research showed columns should be no more than 3 stories, so if splices are expensive it may be good to go with one splice only, at 3rd floor. ?Makes it about a 32 foot column which I imagine can be easily transported.

SteelPE- I took from the attached post that the Kirk, upon researching more, found the column should only be 3 stories tall, 3x15= ~45'. Perhaps I'm misreading. If column is 60', yes I would splice.

 

[steellion]

I would keep the outside dimensions of the HSS section the same and change only the thickness of the HSS column walls at the splice. Don't go too thin with the HSS walls because it will cause you issues with the beam connections. I would definitely recommend W-shapes over HSS for a 4-story building, but HSS can be done. Typically I have only used HSS columns for AESS columns because HSS costs ~40% more than W-shapes. You can make up for this on a 1-2 story building by having columns with less weight, but probably not 4 stories. Your first RFI from the steel fabricator will likely be: "Can we use W-columns instead?"