craigburger
Geotechnical
- Sep 16, 2002
- 1
I've been asked by a civil engineer and municipality to provide criteria for design of kickblocks for water distribution pipes.
The question came up because the poor soils on the site likely don't have a bearing capacity of 3,000 psf and the public works department standard detail states "based on 3,000 psf soil bearing capacity".
The lateral forces caused by pipes and water hammers seems to have little to do with the concept of bearing capacity, and I would use a passive earth pressure and friction between concrete and soil approach.
Anybody encounter this before? I checked another municipality, and their standard detail states the same assumption about bearing capacity.
My preliminary calculations indicate that the friction component is relatively small compared to the passive earth pressure component. To have a capacity of 3,000 psf, for a burial of 5 feet, you would need a passive earth pressure equivalent fluid pressure of close to 600 pcf, or a passive earth pressure coefficient of close to 5, which not too many soils would have.
Any comments are appreciated.
The question came up because the poor soils on the site likely don't have a bearing capacity of 3,000 psf and the public works department standard detail states "based on 3,000 psf soil bearing capacity".
The lateral forces caused by pipes and water hammers seems to have little to do with the concept of bearing capacity, and I would use a passive earth pressure and friction between concrete and soil approach.
Anybody encounter this before? I checked another municipality, and their standard detail states the same assumption about bearing capacity.
My preliminary calculations indicate that the friction component is relatively small compared to the passive earth pressure component. To have a capacity of 3,000 psf, for a burial of 5 feet, you would need a passive earth pressure equivalent fluid pressure of close to 600 pcf, or a passive earth pressure coefficient of close to 5, which not too many soils would have.
Any comments are appreciated.