Just received the following from client

[Pmtottawa]

Just received tr he following from client.

"Groundwater will reduce ULS but not SLS bearing resistance. SLS currently governs, and the groundwater will not reduce ULS bearing resistance to the point that ULS governs at our site for the contemplated footing depths. We will have more than Toro’s minimum 100 kPa factored bearing resistance with 1.0m, 1.2m or 1.8 m deep footings (to bottom of footing), with or without groundwater).

Geotechnical report found no groundwater during his boring.

I have a 9ft x 9ft ftg sitting 5ft below ground and when they dug, they found seasonal groundwater at 4ft.
Even if I raise the ftg to 3ft I'm still to reduce bearing capacity as I am within 2*width of ftg..

Confused.

P

 

[BigH]

Are you worried about shear failure of the footing or settlement? What is the nature of your soil - granular (and whether loose, compact or dense) or cohesive (consistency - soft, firm, stiff)?

 

[Pmtottawa]

Soil is mostly clay and in the great white north... so mostly frozen during the year.

Worried about settlement most of all.

P

 

[dik]

Clay is not so much a problem, but it if often accompanied with silt... a much bigger problem. In Winnipeg, it thaws for July 1. When I was younger, I put in fence posts and found frozen ground 2 or 3' down in June...

Our highly plastic clays can retain moisture at extremely cold temperatures... The water molecules cannot expand and it remains in a supercooled condition.

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

-Dik

 

[Pmtottawa]

dik...

this project is in the Yukon.

no mention of water in the test pits that the Geotech did.

they began digging and hit basically a river at 4'.

 

[dik]

**It happens... Most geotech reports have a disclaimer that the information is valid at the location of the borehole... Most clays that I've encountered do not readily have free flowing water.

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

-Dik