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File Storange Question

File Storange Question

File Storange Question

(OP)
I have a project that I am currently working on that has been in the office for 9+ months. The project is a 3 story office building (2 floors and a roof). Construction is to be out of open-web steel joists supported by beams/joist girders and steel column (to mimic 2 other building we have completed for the client). The project was expedited at the request of the owner due to lease agreements. The project came to a screeching halt 3 weeks in and has sat for 8 months until we received the go ahead to proceed a little over a week ago. The reason why this is important is because pricing was started with the preliminary drawings we were able to produce.

One change the owner would like to make is to add file storage to the second floor of the building. We have been told that the shelving will weigh approx. 410# per unit with two units back to back (820#). At a floor area of 6 square feet this will equate to a load of 140 psf for the shelving. My question is in regards to the isles. Assuming a 3’ wide isle and an isle load of 40 psf would equate to an average load of 78 psf (the building was designed for 80 psf).

The three options I am considering.

1) Design the entire floor for 140 psf (seems like overkill)
2) Design the entire floor for 80 psf (might be light)
3) Design the floor joist system for 140 psf and the girder/column/foundation system for 80 psf.

I like option #3 as it captures the decreased loading in the isles in-between the shelving.

What would the community do in this instance?

RE: File Storange Question

My first instinct was to use the 125 psf light storage load over the specified storage area.

RE: File Storange Question

(OP)
azcats, that was a thought as well. I considered adding that as a 4th option, but that doesn't quite suffice for the loading proposed by the shelving units.

RE: File Storange Question

I'd double check that the 410 lbs includes storage media, got burned on that once before.

I tend to err on the conservative side and would go option 1: 140 psf everywhere, also gives them flexibility to re-arrange the storage space as needed without having someone look at it.

RE: File Storange Question

If I was unclear, I meant to use 125 psf over the entire area where the racks and aisles exist for storage. Not just under the racks. So a smidge under option 1.

Library stack rooms are designed for 150 psf and they specify a 3' corridor and 9' max height.

Any chance these storage racks would be removed for rolling storage racks w/ more capacity in the future?

RE: File Storange Question

Loading seems low for rolling storage... how high are the filing cabinets... You might be looking at 50-6060-70 pcf for the volume of the cabinet. Also steel deck does not do well with rolling loading... you might consider using a solid slab in the storage area and design the storage area for the actual loading.

Dik

RE: File Storange Question

from 7-10 commentary:

RE: File Storange Question

The 150 psf if for filing cabinets that are 'fixed' complete with access rows. When it is possible to stack the filing cabinets in a dense pattern without space between, you have to design the area for the actual loading. Often cabinets are 6 drawers high, sometimes 4 and sometimes 10... The 150 psf may not accommodate the actual loading which should be designed for (This is likely code stipulated for storage areas).

The design loading assumptions should be clearly provided in the area by signage stipulating the max cabinet height and loading.

Dik

RE: File Storange Question

I'd also go with the ASCE value of 150 psf.

Trying to guess the exact weight of the file units, both now and whatever they decide to add in the future, seems like a mug's game. If you go that route, I'd add at least 25% to the calculated load (the same strategy I use for rooftop mechanical units, which seem to have the Heisenberg-like property of never being certain). 150 psf is the most defensible number since you can point directly to the code provision, and it's hard to see it having much of a cost impact unless you're talking about an entire floor of storage.

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