Parking Garage Live Load - Valet

[bsh117]

The current ASCE 7 references a uniform live load for parking garages of 40 psf. This is reduced from the previous versions which referenced a 50 psf live load. Within the commentary, it appears to also allow for this same 40 psf loading even if the parking garage is utilizing valet parking or stacked parking over conventional parking.

What do you all say? Am I interpreting the commentary (ASCE 7-10) C4.7.4 correctly?

Thanks!

 

[DETstru]

I'm assuming you're referring to tandem parking, not vertically stacked parking.

I don't think the load increases that much to warrant anything over the 40 psf minimum. A compact parking stall is 16' x 8' and the average vehicle weight in the US is 4,000#. Let's just use 4,500# for the sake of it. That's 35 psf over your entire floor even if there were no drive isles.

The code commentary indicates that 40 psf is plenty (especially given the 1.6 LL factor) even for tighter special purpose (valet) parking.

 

[Teguci]

Unless you need to park armored limousines side by side, you are good to go using 40 psf. I would not apply this to mechanical parking unless you can control the weights of the cars going into the stacker. To envelope the mechanical parking take 40 psf times the number of cars that can be placed there. That higher load can be limited to just the plan area where the stacker will sit (usually near the end of the span).

Do not host dance parties on parking garage deck -

https://www.youtube.com/watch?feature=player_embedded&v=hr3HTkkpvtU

 

[bsh117]

Thanks for the input! Yes, when I'm referring to stacked parking, I'm thinking about tandem or "double parking" rather than a vertical mechanical stacking.

Thanks again!

 

[MrHershey]

It's 40 psf. Vurrent codes don't allow you to reduce loads for parking garages except for up to a 20% reduction allowed for members supporting 2 or more floors. Given the UBC (at least 97 edition) allowed up to a 40% reduction with no restrictions, you could be designing for a higher load now than you were before if your trib is high enough.

SK Ghosh has a good article on the change from way back when: Link (PDF).

Also since you're talking valet and we had this discussion in our office a while back, a good blog post on public vs. private parking garages for determining seismic mass, again from SK Ghosh: Link