Friday, November 23, 2012

Housel's (1929) Method of Determining Safe Bearing Pressure from Settlement Consideration - Foundations.

The method suggested by Housel for determining the safe bearing pressure on settlement
consideration is based on the following formula

where Q = load applied on a given plate, Ap = contact area of plate, Pp = perimeter of plate, m = a constant corresponding to the bearing pressure, n - another constant corresponding to perimeter shear.  


To determine the load Qf and the size of a foundation for a permissible settlement Sf.

Housel suggests two plate load tests with plates of different sizes, say Bl x B1 and B2 x B2 for this purpose.


1. Two plate load tests are to be conducted at the foundation level of the prototype as per the procedure explained earlier.

2. Draw the load-settlement curves for each of the plate load tests.

3. Select the permissible settlement S,. for the foundation.

4. Determine the loads Q{ and Q2 from each of the curves for the given permissible settlement Sf.

Now we may write the following equations

for plate load test 1 .

for plate load test 2.

The unknown values of m and n can be found by solving the above Eqs. (13.4a) and (13. 5b).

The equation for a prototype foundation may be written as

where Af = area of the foundation, Pf = perimeter of the foundation.

When Af and Pf are known, the size of the foundation can be determined.

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