Load Limit For 3 Inch Concrete Floor

Those must be some well built file cabinets you have there! I have some good sized 5 drawer units I got from the local air base that are way over built and I would say they don't weigh half that.

As far as the OP's engineers advice I think he is way off as well. 40# per sq foot for a 3 inch thick reinforced concrete slab with corrugated steel underlayment on 24" spaced structural members seems way low. To be honest my books say the 3" thick slab weighs around 35# per sq foot alone.

To be honest my shop roof is rated for over 3x that per sq foot and thats nothing but ribbed sheet steel on 2" x 4" cross members set on 30" spacing all held up by 2" x 6" trusses set on 48" centers over a 32' span and I can walk all over that with my 250#'s without kinking the sheets let alone falling falling through.

The guy actually said 40# and then said maybe it was 140#, but he was referring to the live load, which excludes the dead load weight of the structure itself. 140 would actually be just about right as I figure the 42" 5 drawer stuffed full of paper would come in at 136/Sq Ft even in a fine heavy cabinet as described previously.

• View larger
• Two drawer
• 28-3/8"H x 36"W x 19-1/4"D
• Charcoal
• Letter or legal size
• This product is made from 30% post consumer materials
• Each drawer provides 2.96 cubic feet of storage
• Weight: 132 lbs

Do you ever add anything constructive?

His 40 lbs a square foot sounds more like the floor load. I don't think you would have a problem unless he is going to fill the room with these file cabinets. You have to look more at the structural steel holding the slab up and what it can handle.

The 36 X 18 would have to weigh filled more then 180 lbs to exceed the given load limit.

If he's talking about 140 psf live load, that should be ok if we are only talking a few of these files.....

http://www.eng-tips.com/viewthread.cfm?qid=17038

square foot or inch??

Whoa back. 40psf is an average for the floor and in some domains would be acceptable. This average includes the equipment and the unloaded spaces between. The information you supply is not sufficient, the deck could be composite or non-composite and several different weights, the wire size and specification is unknown as is the strength of the concrete.

More normal would be 50# plus 15# for partitions plus an allowance for MEP. If designated for library use, it should have been designed for the actual usage.

No-one here can see the installation.

No-one here is liable in the event of a structural failure due to inappropriate advice being followed.

So the best thing to do hire a local Structural Engineering Consultant to investigate and prepare a report. Yellow Pages?

Good point but no one ever answers at the city inspector's office here in Austin TX

Dear Steven,

All you write makes no sense.

Give us the kind of joists - and span and we get somewhere. Not the concrete but the joists are determinant.

If you do not know, measure them and make a sketch for us.

36 ft span, 20 inches top to bottom, 3-58 across the bottom and 9/16 thick cros braces

nice shot but it really isn't the most critical one you could have taken, those trusses are transferring the floor load to a column or a wall, how they are attached to them is where the rubber meets the road! but we love pics here, good job. have the truss rating by chance? all kidding aside if you have your plans especially the "as builts" you should be able to read the notes and specs to find out what you need to know. you really want info on "dead, as well as live loads" good luck but I doubt you'll be shocked to find out you have several tons of play left

Check google for

load steel joists

span steel joists

The Newmill catalog that shows has it all. Just check the channels used, especially the bottom one, so that it is fat enough, compared with the catalog ones.

The load tabels:

Deduct the weight of the joist

Deduct the weight of the sheet

Deduct the weight of the concrete

Deduct the weight of the mesh

In your case the load per square foot is less important, more the total weight on the joists. Check further and come back if you need more help.

You will certainly find a joist that is similar to yours qua dimensions. In case of doubt use a size smaller before you check the span load tables and a size bigger for the joists own weight table. Determine how big your floor is in sq. feet and count the joists and girders. One detail: I asked to check that the lower channel is fat enough.

Modern joists have L channels below. Yours seems to be a Omega or something. The section of this in particular is under most stress and the section needs to be sufficient to make a comparison with 2 L channels' section.

When you go to the load section, you play pretty safe taking the dynamic values. (These are significantly lower than the static load) I always use them, calculating flat roofs where I live (because of the hurricanes)

As Fredski says, the joists' connection with walls (or girders and pillars - but I guess you'll have none since 36 feet is a short span) need to be checked too. Cracks close to the seats in the walls are a bad sign.

Other than that you might have plenty of extra load capacity. (contradictory to what Fredski says)

But again, check the tables first and once you have the results, come back and then, with the gathered knowledge let an "official" or registered structural engineer state it.

This way you'll sleep tight.

Better still, get that hired Structural Engineering Consultant [#9↑] to measure them instead.

I've never seen or heard of a building being damaged by file cabinets. Has anyone? Think

Yep. These people have:

an assemblage of matter a building constitutes does not.

I have not but the point is still the same, assuming this place was designed and constructed correctly it will certainly have a square inch or foot rating for loading. regardless of how much steel and concrete it contains it will have a design limit that shouldn't be exceeded. by the way the concrete aspect of the floor is more about sound attenuation and vibration control.

I echo the sentiment about consulting a professional because no one here has access to this building or any of the plans used in its construction, there is no "rule of thumb" that applies here. weight is weight regardless if that weight is paper, lead or feathers. a file cabinet is no different.

To elaborate along the lines of Bricktop's reasoning, you should be able to go to the town/city hall and pull the submitted dwgs for the building permit and the load limits will be listed on the concrete structural dwg which should include the structural steel beams in the calculation. The builders would also have to submit engineering calculations to verify these dwgs which should be available from the town/city hall.

UFG

...and if the drawings are unavailable, get that Consultant [#9↑] to produce them in the Structural Report. Remember that what was "as built" when the building was constructed isn't necessarily the case now.

I would contact the concrete supplier as they are the ones that have to mix the concrete to specifications. Your question as to the load should be easily answered by the supplier.