Columns - HSS or WF

[JAE]

What are most of you specifying for general steel framed buildings - primarily industrial/warehouse types?

We generally see a lot of wide flange columns used in these kinds of buildings but when you look at the relative weight-stiffness and weight-strength ratios, the tubes look very good.

But if so, why do we see so many WF columns used?

 

[OHIOMatt]

I prefer to use tubes in cases like this. Unbraced lengths are the same for all sides, so utilizing a sysmetric member makes sense to me.

I just complete a buildin of this type, but used WF columns. The original drawings showed HSS, but the owner said "tubes are expensive". No convincing him otherwise, so we went to the heavier WF section.

So I think that HSS members suffer from a legacy of greated expense in production and fabrication. These costs have come down, but the preception persists.

 

[ToadJones]

Used to them....connections are easier.
Plus, industrial buildings & warehouses are usually made up of a series of bents or frames with loading primarily resisted by the strong axis of the frame and bracing in the opposite direction.
In other words, WF's put the steel where you need it.

 

[jberg]

Agree with Toad. If you use HSS columns in a moment frame, I always worry about bending that face of the HSS. That is where the WF's have an advantage.

JWB

 

[JLNJ]

If you are working on a State project which requires domestic steel or a LEED project where you want to get the steel from within 500 miles, tubes may not be the way to go. Many are rolled in Canada.

 

[OHIOMatt]

To clarify my position. The buildings using HSS columns use pre-cast concrete, tilt walls or CMU as shear walls on the exterior for later loads. The columns are interior and taking gavity loads only.

I typically do not use HSS members in moment frames, but they do work well in braced frames.

 

[SlideRuleEra]

JAE - For industrial applications where long term corrosion is a real possibility we used WF sections to make monitoring of section thickness easier. If corrosion is not a consideration, of course that reason goes away.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[SlideRuleEra]

Also, WF is probably more resistant to accidental impact from mobile equipment (forklifts, etc.). And, if damaged, easier to repair than HSS.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[SteelPE]

We usually use HSS sections in areas were connections is not that large of a concern. If the connections are complex, we will use WF sections as I feel the connections are easier to make.

Also, as stated above, I worry about HSS moment connections and the side wall of the column.

 

[msquared48]

Easier detailing and longer record of possible connections with WF sections.

Pre-qualified weld issues in detailing.

Tubes are more suited for columns than beams, but WF's are good for both.

Tubes used to be more expensive and less available at times in certain sizes and grades.

Mike McCann
MMC Engineering

 

[ash060]

I had an issue that msquared48 metioned of the per pound price of steel for HSS being much higher than wide flanges. Rectangle being the highest per pound.

It was enough for us to go from HSS columns to WF columns

 

[msquared48]

Also, our nemesis, Architects, prefer tubes in general over WF's when exposed. It is a fact that Architects like to expose things.

I guess it's because they are standing there with their mouth open, closely mimicking the shape of the tube sections?

Mike McCann
MMC Engineering

 

[dik]

JAE... I try for continuous construction with the beams framing over the tops of HSS columns... least costly for warehouse type of structures and often use W shapes at the ends (walls) for lateral.

Dik

 

[connectegr]

Use WF shapes for columns. Connection design with HSS columns in braced frames and moment frames is more difficult and more expensive to fabricate. For simple framing, shear only beams, HSS columns are fine provided the wall thickness is sufficient for face welded shear plates.

The fabrication of cutting, slotting, and re-welding of HSS columns is labor intensive and expensive for fabricators. Expecially when connections are orthogonal. Wide flange columns are generally beam line items, with cutting and drilling by CNC. The addition of stiffeners and web reinforcement, can be costly, but can also be off-set by column weight selection. This fabrication cost and additional material cost does not make HSS columns an equal alternative to WF columns.

http://www.FerrellEngineering.com

 

[ToadJones]

M^2-
The architect comments are making me laugh out loud.

also, I have worked on power jobs where HSS was forbidden unless all kinds of fabrication requirements were met, namely, all ends of exposed tubes had to be sealed with cap plates and welds for fear of coal dust accumulating and.... KA-F^&%$'N BOOM!
But, once the ends were "sealed" any possible moisture accumulation inside could be lead to other problems as we have seen in other posts with water freezing inside HSS.

For center columns in warehouses or Home Depot/Lowes/Wallbillies, HSS is probably the best choice.

 

[dik]

A simple cap plate and base plate fillet welded to the the top and bottom of the HSS plate with 4 bolt holes... Lateral taken by end columns and girts to roof diaphragm into X-bracing... slikker than...

 

[connectegr]

Cap plate and baseplate, is the simplest case for HSS columns. My comments were primarily concerning multi story construction. Where connections to HSS columns occur at intermediate levels, and require thru-plates or stiffeners. The HSS walls may require slots and cuts in length (which require CJP repairs). Bracing connections have increased eccentricity, which require additional bolts and connection size. Cruciform conditions may require weldments which are concealed within the HSS, and require cutting and repair of the HSS.

http://www.FerrellEngineering.com

 

[hokie66]

For axial only members, tubes.
For columns subject to bending, WF.

 

[JAE]

hokie66,
the tubes tend to have larger I, S, and Z values (per pound). That is the argument in favor of tubes.

Why "buy" WF shapes almost twice as large to get the same stiffness at half the weight?

 

[hokie66]

JAE,
But that is the case in only one direction, right? I suppose it depends on whether you are comparing the tubes to relatively square column sections or beam shaped sections.