## Elastic Methods for Strip Load

## Elastic Methods for Strip Load

(OP)

In Foundation Analysis and Design, Bowles 4th Edition, he recommends discretizing a strip load into a finite number of point loads, then finding the pressures via Boussinesq's equation for a point load acting on a semi infinite elastic mass. Then adding the pressures caused by the point loads to find the pressure on a retaining wall due to the strip load.

I have compared this method to (what I thought was) the integrated form of the Boussinesq formula for point load acting on an elastic 'mass'. The results do not match. You may say this is due to the incorrect Poisson's ratio being used (plane strain vs triaxial) however I have checked this as well and even for a corrected Poisson's ratio the difference is large.

See attached.

This has been a real thorn in my side for a long time. Can any one shed some light on this?

Thanks in advance!!

I have compared this method to (what I thought was) the integrated form of the Boussinesq formula for point load acting on an elastic 'mass'. The results do not match. You may say this is due to the incorrect Poisson's ratio being used (plane strain vs triaxial) however I have checked this as well and even for a corrected Poisson's ratio the difference is large.

See attached.

This has been a real thorn in my side for a long time. Can any one shed some light on this?

Thanks in advance!!

## RE: Elastic Methods for Strip Load

## RE: Elastic Methods for Strip Load

EIT

www.HowToEngineer.com

## RE: Elastic Methods for Strip Load

Now if i use 10 point loads of 1 ton and calculate the stress at the same location Iget 0.0247 tons/m2, ie 90% of the previous value. Is that what you call "not even close" ?

## RE: Elastic Methods for Strip Load

EIT

www.HowToEngineer.com

## RE: Elastic Methods for Strip Load

## RE: Elastic Methods for Strip Load

As for the chart - Interesting, I will look into this and see how it compares.

Do you use y = 1.0 for infinite strip load?

EIT

www.HowToEngineer.com

## RE: Elastic Methods for Strip Load

## RE: Elastic Methods for Strip Load