ruck loading on an elevated slab

huangyhg

truck loading on an elevated slab
i have an elevated plaza/parking slab on a condo project we are working on.  there is a daylight basement type of parking beneath the building, and an area of parking on the 1st floor slab.  there is retail shops and restaurants going in on the first floor, so the owner wants to have delivery type trucks be able to drive in on the elevated deck to make their deliveries (ups trucks, bread trucks, small delivery vans, etc.).  i am trying to get a good idea for what the design load is for those smaller type of trucks, short of 250 psf used for highway loading.
furthermore, we were thinking of putting some type of gate over the driveway of the elevated slab to prevent taller vehicles from driving on to the slab, but i believe a lot of the delivery type of vehicles are just as tall as full sized semis.
anyways, is this something we should have the owner avoid?
find a job or post a job opening
if the ibc applies, then 250 psf is probably the appropriate minimum.  you probably want to design for big truck loads anyway because of fire trucks.
maybe an h15 aashto truck loading?
you need to design for the specific wheel loads including overlapping stresses. refer to the aashto spec for the appropriate wheel loads. don't forget to consider the possibility of two vehicles passing if you have two way traffic.
i designed a project a number of years ago for an hs20-44 loading and a few years later i wassurprised to see a fully loaded concrete truck on it!
we may be forced into the fire truck loading - the architect met with the fire marshall today . . .
as for the height restriction bumpers, we would do that, but the owner evidently wants delivery trucks to have access to that part of the structure, which are just as tall as any large truck that we don't want to block.  so we will either design for trucks or we won't and put up a restriction bumper.
i realize that we need to check for the point load conditions for either an h20 or h15 truck, but to get into the initial ballpark, it would be easier to put a straight psf onto the slab.  where does that 250 psf for highway loading come from?  everybody seems to know/use that number, but i haven't ever seen it referenced anywhere really specific.  
it is also interesting to note that the 200 or 250 psf is often used for a highway surchage on a retaining wall.
del2000,
i believe the 250 psf was used quite extensively over the years for sidewalk designs in urban areas where the downtown building's basements extended out to the street curbs and the sidewalks were actually concrete suspended slabs.  
the fear was that in a fire, the firetrucks would drive up on the curbs, or delilvery trucks might do the same and the 250 psf was supposed to be representative of those two occurrances.  
now i'm not sure that 250 would be always equivalent to an hs20-44 truck wheel load.  but it's probably not too far off.
check out thread #507-27824. for a fire truck i would start at a uniform 350psf and then check out the actual axle loads imposed on the slab. good luck.