SOIL BEARING FOOTING PRESSURES

Question

SOIL BEARING FOOTING PRESSURES

cap4000 (Civil/Environmental)

(OP)

31 Oct 03 08:47

Can someone explain why the difference between these two methods. The first one is the typical 2V:1H with the Boussinesq pressure isobars. Between them there seems to be large pressure differences for both Spread and Continuous Footings.

Focht3 (Geotechnical) · Answer 1 · 2003-10-31 09:47:45

What are you doing with them?

Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.

cap4000 (Civil/Environmental) · Answer 2 · 2003-10-31 09:57:30

In response to the Focht3 question. I am trying to figure lateral pressures from spread and column footings against existing foundation walls at varying depths.

Focht3 (Geotechnical) · Answer 3 · 2003-10-31 10:03:11

Then use Boussinesq or Westergaard - the 2:1 distribution is for estimating vertical pressures only. Poulos and Davis' book includes solved equations, as well as charts, for evaluating the lateral pressures.

By the way, were the pressures you calculated using the 2:1 approach about twice as high as those from Boussinesq?

Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.

BigH (Geotechnical) · Answer 4 · 2003-10-31 14:46:12

Poulos and Davis is a great reference (Elastic Solutions for Soil and Rock) and should be in everyone's library. Newmark has a lateral load chart you can use. I'll have to confirm, but for surcharge loadings on non-yielding walls (footing near the wall but founded "high up") which you might have, the lateral pressures are, I believe, to be doubled. I'll try to confirm this.

Come Join Us!

Posting Guidelines

Related Projects

SOIL BEARING FOOTING PRESSURES