Is it possible

[SLaryea]

Hi members

we all know we can conduct analysis from plate bearing tests to obtain:
bearing capacity, CBR, stiffness and settlement.

I've done this for a pad and strip foundations in the past but wanting to check if it is possible to undertake the analysis to obtain the settlement of a raft foundation using PBT results?

Any references to support would be most appreciated

thanks a bunch

 

[EireChch]

Plate bearing tests should only be used to get a CBR for pavement, and to check stiffness of thin layers of fill.

For anything else its useless i think.

In short, no, you cant use a PBT to do any kind of meaningful assessment for raft foundation.

 

[MTNClimber]

The zone of influence of a raft foundation is very large compared to the zone of influence of the plate. It would be highly inaccurate to use PBT results for anything other than pavement design and to check the soil's bearing capacity for small-diameter footings with large loads, such as equipment outriggers.

 

[geotechguy1]

To be honest I think they are useless even for a moderately sized pad or strip footing. You have to think about the zone of influence of the footing / strip footing / raft vs the zone of influence for the plate. A soft layer at 1.5m depth could govern load deformation behaviour of the full scale footing but have zero effect on the reaction of the plate.