NBC 2005 Parking Garage Live Load?

[gmf]

We are working on the removal and replacement of an existing 8 inch thick parking garage slab at an existing hotel. The slab supports an exterior above ground parking lot (a drive through area is provided in front of the hotel for drop-off and pick-up), and is suspended over a single level underground parking garage and portions of the interior basement.
Table 4.1.5.3 in the National Building Code of Canada indicates that we use a use/occupancy load of 2.4 kPa for passenger car garages, but further down indicates 12.0 kPa for "sidewalks and driveways over areaways and basements".
As such, we are unsure whether to use 2.4 kPa or 12.0 kPa. Any help or clarification would be greatly appreciated.

 

[SkiisAndBikes]

gmf,

The 2.4 kPa design live load typically accounts for regular automobiles in a parking garage. As the space above the garage slab sounds like it is above grade and a drive through area at the front of a hotel, you will need to determine whether the area could be accessed by fire trucks, garbage trucks, buses, snow removal equipment, etc.... If so, then a design value of 12.0 kPa may be more suitable. Typically for podium slabs around buildings, at least a portion of the slab is designed for heavier loads. Any areas not required to be designed for the heavier loads should have some form of barrier (height restriction barrier and signage) to prevent errant heavy vehicles (fire, garbage and snow removal vehicles) from travelling onto any portions of the slab designed for lower values.

 

[mdavis1]

Since the underground parking garage has the loading from the pick-up/drop-off area above it, I would use the 12kPa loading. That area is going to have sidewalks and the pick-up/drop-off area is a driveway. I guess it depends on how much of that slab is under those areas, if all or most of it is, go with the 12kPa.