Industrial Warehouse

[SteelPE]

I have a project that I designed last year that the client would like to make some changes to.

Current project is designed using IBC 2015 and is a single story warehouse with an eave height of 41'-0". Building utilizes open-web steel joists supported by joist girders and steel columns. Perimeter is clad in insulated metal panels supported on cold-formed girts and steel beam-columns (steel W14 columns). Lateral forces are resisted by concentric brace frames.

For some reason, the client would like to increase the eave height to 55'. I don't have many issues with this other than the fact that I have never gone this high before with this type of structure. At first glance, we will need to increase the column depth to limit deflection of the system..... however, there are not may W16 section options..... so that may push me to W18's. Column flange bracing is anticipated along the height of the column (at roughly 15'-20' intervals). Does anyone have experience with industrial buildings of this height? Are W18 columns common?

Just need a bit of a sanity check.

 

[JAE]

Probably not "common" but a 55 ft. open building isn't "common" anyway.

So determine the required shape based on strength and stiffness - that is what is commonly required.

 

[DanKile]

For a 55' tall, I would start at W18. I designed a rock climbing gym a couple years ago and used W21 for 60' columns.

You are getting to the limit of most steel mills for length. You can check with the fabricator what they can do for a range of sizes, or you may consider adding column splices.

 

[JAE]

I think the steel mills - for WF shapes - typically can go longer - at least 60 ft.

 

[phamENG]

Haven't designed any, but I did work in a steel mill for a short time. We had clear heights ranging from 10ft to 120ft and columns ranging from W6s to pairs of W24s laced together. I think you'll be okay at W18.

 

[SteelPE]

We have asked a few fabricators about shipping issues.... all said there were a few issues, but nothing major that they haven't dealt with in the past so don't worry about it.

 

[DanKile]

Mills probably can do 60'. I was going off our supplier's list of shapes. Most of the shapes listed have 60' available, but not all.

 

[civeng80]

I designed and built a few in my days, never this tall. My tallest about 30 ft. (9m)
As a matter of interest whats the span of the portal and your analysis software?

 

[JLNJ]

If you have braced frames, why does the column depth have any bearing on your deflections?

If the columns are loaded axial-only, square tubes would be the most efficient.

 

[dik]

Can you 'plate' the columns across the toes to increase the ry value to increase the allowable loads? I've done that often. One included a structure where the columns were either 80' or 60' (auto plant in Windsor). It may be possible to insert a new part of column at the bottom. In addition, the plating can stop within a couple of feet from the very top and bottom to avoid issues with existing fasteners.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[phamENG]

JLNJ - I believe he is talking about wind columns at the perimeter supporting the insulated metal panel walls out-of-plane.

 

[JLNJ]

Point well taken, but I still like tubes here,(maybe rectangular) so you are not left wondering if a girt offset several inches from the face of your column flange braces the column in the weak axis.

 

[SteelPE]

Yes, phamENG has it right. The insulated metal panel/girt system will induce local bending in the column that we need to design for.

Our bracing system around the perimeter will need to be done in a few "lifts" that is, we will be stacking multiple levels of inverted V bracing and V bracing to reach the roof. It is at these vertices were we will consider the perimeter columns braced. We may even double up on the girts at these elevations, but I am not sure about that yet. With this type of bracing I don't see why the perimeter columns wouldn't be considered braced in the weak direction (at the vertex location of the concentric bracing).

 

[JAE]

With inverted V and V bracing are you essentially creating an "X" brace with the pair?

For typical chevron bracing (inverted V) you need to be careful that your horizontal girt is laterally braced out of plane of the wall at the top of the inverted V.

 

[SteelPE]

Yes, the idea is to create a "2-story" X brace...... but it's not really going up 2 stories as the building is only 1 story high (at 55')

 

[lexpatrie]

It looks like the VAB is 526 feet tall with a single story....

https://en.wikipedia.org/wiki/Vehicle_Assembly_Building

I know I saw some research on components and cladding for something NASA adjacent that wasn't quite that tall, more in your range, but I can't recall enough details to find it again. That's the curse of google. You always find something interesting with the wrong search term and then can't find it a second time. I thought it was a Peterka article about wind deflectors to reduce uplift on the roof membrane but maybe I have the author wrong. You aren't really asking about C&C loads anyway, but the point was it's another atypically tall building, similar to yours, so it's not unique. Unusual but not unique.