Weak Soil Foundation type 3

[Gus14]

My contractor friend shared with me 4 borehole reports for a two storied building with an area 40x50 meters. I attached the soil report. I am not involved in this project but curious as how to deal with this situation
The columns spacing is approximately 10 meters so each column load is in the range of 1000 kn.
There is no basement, so the embedment depth is dependent on the foundation design.

1. What further tests are required? Why ?

2. What embedment depth should the designer assume ? and what type of foundation? single footings on piles ?
how deep should the piles be ?

3. What soil strength should be assumed in the design ?

I know the answers are not simple, so I am only asking for guidance as I have never dealt with a similar situation before.

Borehole test report file

https://files.engineering.com/getfile.aspx?folder=6200ddf9-0364-47f5-b504-d9fe7e80e6b6&file=STR.pdf

 

[jerseyshore]

Most structural engineers are going to need a soils report with design values and recommendations based on these borings from a geotech. There are not many structurals that I know who write their own reports, maybe some site civil guys, but rarely structural. I know my insurance wouldn't cover me performing geotechnical work.

 

[raligt]

Send your information to a Piling Engineer and see what they think. They usually give preliminary advice for free, in my area anyway - not sure about Kuwait

 

[Gus14]

Thank you jerseyshore and raligt for replying.

Most structural engineers are going to need a soils report with design values and recommendations based on these borings from a geotech.

Around here usually use the strength shown on the tables to design the foundation. The shown report is the only report they issue, on the report they said they recommend using deep foundation or mat foundation if SP, SP-SM sand group is present which happens. Still they claim no liability.

I am puzzled as to why the soil becomes weaker as we go down, I don't know how that will effect settlement of the structure. I know that soil pressures will spread at a 45 degree angle but still the some of the lower layers show very small number of blows. ( 6 to 10 )

Send your information to a Piling Engineer and see what they think. They usually give preliminary advice for free, in my area anyway - not sure about Kuwait

They will probably recommend using raft or pilling but still I don't know how pilling would work since the soil below is still very soft.

BTW, How did you know I live in Kuwait ?

 

[raligt]

Yes I am sure the Piling Engineer would ask for deeper boreholes to be done to find good soil/ rock. I dont think they would be able to design a foundation solution based upon the weak soils noted in the bores.

When you click on a username, at the end of the 1st paragraph it gives a location . For example mines is EN,GB

 

[BAretired]

BTW, How did you know I live in Kuwait ?

It's in your member profile.

I would think a Franki pressure injected pile would be the way to go.

 

[Gus14]

Yes I am sure the Piling Engineer would ask for deeper boreholes to be done to find good soil/ rock. I dont think they would be able to design a foundation solution based upon the weak soils noted in the bores.

I understand now. Thank you

Thank you BAretired for replying.

I would think a Franki pressure injected pile would be the way to go.

Will take a further look into it.