ᐅ Soil bearing capacity and modulus of subgrade reaction

Created on: 13 Nov 2015 00:17
C
cumpa
Hello.
I had a soil report prepared. It states:

"To accommodate settlements / differential settlements of up to 1.5 cm (0.6 inches), a design value for the bearing pressure (Eurocode 7) of 200 kN/m² (18.6 kips/ft²) can be assumed for an effective foundation width of 1.0 m (3.3 ft).
The foundation slab should be designed based on an elastic subgrade. For the design of the foundation slab using a design bearing pressure of 140 kN/m² (13.0 kips/ft²), a subgrade modulus of 9.5 MN/m³ (0.55 kip/in³) should be applied."

In my construction contract, the clause reads:
"The calculation basis is a permissible existing soil pressure of 150 kN/m² (14.0 kips/ft²) and a subgrade modulus of 20 MN/m³ (1.15 kip/in³)."

What does this mean for me?
B
Bauexperte
15 Nov 2015 23:10
Good evening,
cumpa schrieb:

hmm....

I didn’t respond to your private message because I am neither a geologist nor a structural engineer, nor do I have any idea what kind of house you want to build, with which materials, and in what location; plus, I simply didn’t have time. All of this is essential for a reliable cost estimate; rough guesses won’t help you.

You should have checked the foundation recommendations in the soil report or, if you couldn’t read or understand it, called the geologist.
cumpa schrieb:

I signed the construction contract today......and the seller couldn’t tell me anything about the soil report. He said I should wait until the site management/structural engineer reviews it...
I don’t have a good feeling about this

Then you shouldn’t have signed. Although, in my opinion, it doesn’t really matter; if you already own the plot, the extra foundation costs will come to you anyway.

Best regards, Bauexperte
C
cumpa
15 Nov 2015 23:23
I had everything reviewed by a building expert. From the offer to the construction specification and even the contract review, which was done by a lawyer.
So far, I have not received any negative reports regarding ground issues.
I came across these values myself and thought there might be discrepancies between the calculation basis and the geologist’s figures.
I will contact my geologist again tomorrow.
Thank you, Bauexperte, and thank you, Sarius, for the answers.