Frictional resistance and 50% of Passive Pressure
Frictional resistance and 50% of Passive Pressure
(OP)
Hi,
I have a Spread footing where the ratio of Horizontal Load Fa to the Frictional resistance, = Fa/Fr=1.1 <1.5
To increase the Factor of Safety(F.O.S) of sliding, 50% of the passive pressure with Frictional was considered.
However I am not confident with 50% passive pressure together with Frictional resistance of the Foundation.
Because passive pressure would act on the foundation only when the foundation moves, it means that when passive pressure is there no friction is available.
Please suggest me if I am wrong.

I have a Spread footing where the ratio of Horizontal Load Fa to the Frictional resistance, = Fa/Fr=1.1 <1.5
To increase the Factor of Safety(F.O.S) of sliding, 50% of the passive pressure with Frictional was considered.
However I am not confident with 50% passive pressure together with Frictional resistance of the Foundation.
Because passive pressure would act on the foundation only when the foundation moves, it means that when passive pressure is there no friction is available.
Please suggest me if I am wrong.






RE: Frictional resistance and 50% of Passive Pressure
When sliding is a problem, shifting the position of the footing relative to the wall face helps (if that works for your site geometry).
However, the way your sketch is show, there doesn't appear to be much driving force.
RE: Frictional resistance and 50% of Passive Pressure
Mike Lambert