Building owners complying with posted live loads

[vmirat]

A long time ago, in a galaxy far, far, away (like 2009), I posted a question about building owners complying with posted floor load limits (IBC section 106). The question was, how do laymen figure out if they are staying under the posted limit. For example, the recent inquiry to me from an owner concerned a second floor designed for 100 psf. The owner says, "Hey, I weigh 200 pounds, does that mean I can't walk on my floor?". Unfortunately, I never got a very good answer, so I'm re-posting this question.

Obviously, the actual load can exceed 100 psf if it's limited in area. But how is a non-engineer suppose to figure this out? This particular owner wants to use this part of the building for storage. They shouldn't have to hire a structural engineer every time they want to use their building.

 

[EngineeringEric]

Typically the 100psf limit also comes with a concentrated load over a given area (maybe 8"x8") so the 200# guy weighs less than the 3000# concentrated load.

As for the argument... the entire area cannot support more than 100psf all at once. But if it is storage it may need to be reduced if the design live load was reducible. So in argument sake, lets say we have 3' wide walkways between 6' wide storage areas. these storage areas can have 100psf in the storage and nothing in the walkway. I still would not let them do 125psf since we have no load in that walkway.

The psf load is for large areas, it is not a concentrated load. And if we filled the floor with 200# people all standing 12" from each other then it would fail, but luckily we cannot do that since we like personal space.

 

[WARose]

One time I had a boiler house where I had to limit the LL for a level (because of a modification). I basically came up with a sign for the owners to post that limited it to X-number of people in a area at one time. I've had to do similar things where there will be vehicular traffic (for example: near a retaining wall that can't take much surcharge).

Note in the drawings that you posted the sign (and what it said) if you do have to get the owner to post one. In my experience, these signs have a habit of disappearing.

 

[dik]

Usually not too concerned... in a fully loaded parkade with vehicles jammed end to end... the live load may be 15 to 20 psf... generally not a big deal.

Dik

 

[JStephen]

Most people won't think to ask, so it's not a problem. The intent is that you use your magic 8-ball or whatever and discern what people unknown are going to do with that building 50 years down the line.

If they did ask, probably the easiest way to work it is contact the local building department and says "What's this psf business mean, anyway?" Or perhaps google the topic.

 

[drawoh]

For example, the recent inquiry to me from an owner concerned a second floor designed for 100 psf. The owner says, "Hey, I weigh 200 pounds, does that mean I can't walk on my floor?". Unfortunately, I never got a very good answer, so I'm re-posting this question.

Point out the owner that he occupies more than one square foot.

--
JHG

 

[mronlinetutor]

the code says Storage warehouses (shall be designed for heavier loads if required for anticipated storage)
Light
Heavy
125 (6.00)
250 (11.97)

note the word anticipated

disclaimer: all calculations and comments must be checked by senior engineers before they are taken to be good.

 

[dik]

Biggest issue for occupant loading would be exiting requirements, not normally load.

Dik

 

[MikeHalloran]

My experience says that 'storage' means, at a minimum,
multiple rows of full file boxes stacked two high,
or multiple rows of four drawer file cabinets,

... on shiplap or plywood over vestigial rafters
that creak with every step.

The building owner is probably not capable of evaluating 100 psf,
but he doesn't carry anything anyway.

You need to get the message to, and induce calculations by,
the file clerks and laborers
who are tasked with moving a roomful of valuable crap to 'storage'.

I have no idea how to do that.


Mike Halloran
Pembroke Pines, FL, USA