Slab on Grade Loading

[m1ke99]

Do I need to consider slab on grade loads (Dead and Live) on adjacent grade beams or foundation walls?
Is there a difference if I key and dowel the slab into the grade beam?

I have heard mixed advice. The most common approach I have heard is to take 1 meter of tributary width of the slab on grade.

 

[BAretired]

I have never considered any load from a grade slab being carried by grade beams unless it was a structural slab on grade. My normal practice was to allow the slab to float free of the grade beam, i.e. no key, no dowels but there may be situations where dowels are required.

BA

 

[jayrod12]

For slabs on grade with keys and dowels I generally account for 2 feet of slab bearing on the grade beam. The first foot or two is going to act like a structural slab when there's keys and dowels

 

[Ron]

If you have soil above the grade beam, you would consider the mass of the soil as a dead load on the grade beam, though likely not significant. Same with a slab, just a bit higher unit weight and larger influence area. The amount of area you consider is a wild a$$ guess as it depends on whether the slab is reinforced or not.... 2 or 3 feet is reasonable...

If you go through the numbers, you'll likely find that BAretired's approach is fine, but would be good to satisfy your curiosity.