Dead load/service load per floor for a building

[geotechengineer1]

Just curious about the application of this rule of thumb that I've seen before - a dead load of 10 kPa per floor for a preliminary estimation of footing loads. I'm working at a new employer in a new country and they insist that you can take 10 kPa per floor as the service load on a footing regardless of the footing size or the area of the building. So for instance, say you have a 4 story building, they would say the SLS load is 40 kPa on a footing regardless of whether the building is 30mx30m, 10mx10m, and regardless of whether the footing is 0.5m wide, 1m, 2m wide, etc. In previous practice you would only do this if the building was on a raft - so say you had a 10 story building the dead load on the raft would be 100 kPa + the raft weight.

Has anyone ran into this before? I always thought it was 10kPa times the area of the floor per floor and then that would get distributed down to the footings - so for example for a 10mx10m four story building you'd end up with 4000 kN to distribute to the footings and if you had the building ringed in 1m wide strip footings you'd have a dead load of 100 kPa on the footings to use for settlement calcs.

I'm a geotech not a structural so we're just looking at preliminary settlement calcs/footing dimensions but the method they're suggesting seems alarming to me. They want me to take 60 kPa as the SLS load on a footing of a six story building.

Maybe Canadian structural engineers are just over conservative compared to these guys but if I'm understanding their logic then footings that I'm used to having support a two story building they would say are adequate for a 10+ story building.

 

[Settingsun]

I'm pretty sure they're saying the same as you are. The load is obviously related to the floor area, not the footing area. If your footing is supporting 6m*6m area per floor, the load on the footing is 36m2 * 60kPa = 2160kN.