Parking Garage LL
Parking Garage LL
(OP)
Just wanted to confirm that LL for a parking garage is 40 psf (ASCE-7). Seems kinda low, so wanted to double check.
Also, in a multistory parking structure, would you impose full or partial snow load over this 40 psf at the roof level?
Also, in a multistory parking structure, would you impose full or partial snow load over this 40 psf at the roof level?






RE: Parking Garage LL
RE: Parking Garage LL
EIT
RE: Parking Garage LL
I would put the full snow load on the roof in addition to the 40 psf load (both can be there at the same time).
RE: Parking Garage LL
May want to restrict the GVW to 6500# or so, or limit the vertical clearance. Just a thought.
Mike McCann
MMC Engineering
RE: Parking Garage LL
In many cases, the owner will have the snow pushed off to one side and then eventually dumped down to the ground adjacent to the garage. I've seen cases where the snow piles up to 10 feet or more. In one case the precast IT girder cracked the supporting corbel at the column.
Having a snow removal plan in place - and perhaps a snow pile area designated is something to talk over with the owner.
RE: Parking Garage LL
Not applicable to the US, but for comparison, the Australian loading code gives 2.5 kPa, about 50 psf and 13 kN concentrated, for light vehicle traffic areas (restricted to vehicles with gross mass not exceeding 2500 kg. We don't need to add snow except in a very small area of the country.
RE: Parking Garage LL
RE: Parking Garage LL
S = 20 psf+ depending on your site - don't forget snow pile up at the spandrels (usually adds another 300 lbs + linearly along walls)
ASCE Combo 3, 4, or 6 use either Snow or Roof Live Load (not both - check local codes and client requirements for trip ups).
Don't forget to back off the 8 psf for your column load and foundations (except for the roof loading - new provision).
Its all good. I've designed garages for 30 psf (max LL reduction from previous codes) and they are still standing. You will need a head knocker to exclude large trucks from the garage (7'-0" height +/- , make sure you have clearance for the ADA vans though).
RE: Parking Garage LL
How do you figure the load in this area? Is there a code or a paper that would give some guidance for these areas? Is this something you just place on the drawings as a note?
RE: Parking Garage LL
Meet with client and designate an area for snow to be pushed off of the roof.
Design snow gate for that location.
Instruct owner to instruct contractor the requirements in snow removal - Such as no piling up snow above spandrel height and remove snow in small quantities.
Showing the client pictures and explaining to him the cost for not following these instructions may help too. I believe there is a maintenance guide for garages which should be required to follow.
RE: Parking Garage LL
I think for the prelim design/cost opinion I'll use 45 psf non-reducible for all floors and at roof level I'll throw in 30 psf (Chicagoland) snow on top of this load.
RE: Parking Garage LL
Dik
RE: Parking Garage LL
I remember an SE story involving a parking garage that at some point was converted, not sure how exactly, to office space or storage maybe. And sure enough they started having deflection issues, and the SE who reviewed the structure quickly came to the same conclusion we all just did.
RE: Parking Garage LL
RE: Parking Garage LL
H2 hammer weigh 30kN (6600lb) and it has 2.0m (~81 in) wheel line spacing.