Raft Thickness

[Robert-32]

Dear Colleagues,

From your common practice, what is the predicted thickness of a RAFT FOUNDATION for a 13-story reinforced concrete building? Soil bearing Capacity is 200 Kn/m2. The distance between columns is about 8 meters.

 

[dik]

A WAG, I'd look at something initially between 3' and 4' (1m and 1.5m) thick... do a quick moment and shear calc and see what reinforcing and punching shear you end up with. Concrete strength should be about 4ksi (30MPa) min. It'll be a start.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[HTURKAK]

I agree mit dik (Structural). A quick hand calc. assuming bearing stress 150kN/m2 gives 1200 mm flat plate raft thick. But i would prefer grid foundation due to the large spans .



According to the grace of God which is given
unto me, as a wise masterbuilder, I have laid the foundation, and another buildeth thereon. . . .
I Corinthians 3:10

 

[dik]

I've done lots of them without... but to reduce carbon footprint, a grid is likely preferable.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik