swearingen
Civil/Environmental
- Feb 15, 2006
- 667
In all of the geotechnical and foundation books I have been able to round up post-1998, this formula (or one without the factor of 2) is given for the stress on a retaining wall due to a surcharge strip load. In books from 1998 and before, the pi in the denominator is replaced by H, the height of the wall. Obviously, the two equations give wildly different answers the deeper you go. To investigate, I compared a relatively narrow strip loading to a line loading formula and found that the pi aligns nicely.
What gives with this? Did Das find it was an error in '99 and change his books? It goes from H to pi in his books around that time. A Budhu book, "Soil Mechanics & Foundations" has the H in 2000, but others afterwards, including Pile Buck sources, have pi.
On similar note, a subject that has been touched on here before but not resolved to my liking - this formula seems to have a huge effect on short walls when applied at a good distance from the wall. Is this really the case? I put in a wall with a 200 psf surcharge (standard for us) but now they want to put a 20' wide crane pad 8'-2" away at 1300 psf. The wall is only 7'-9" toe to top. The lateral load went from 517 lb/ft to 3378 lb/ft. I expected it to be a good bit more, but it rising linearly with the load at a distance greater than the depth of the wall surprised me.
Any thoughts?
What gives with this? Did Das find it was an error in '99 and change his books? It goes from H to pi in his books around that time. A Budhu book, "Soil Mechanics & Foundations" has the H in 2000, but others afterwards, including Pile Buck sources, have pi.
On similar note, a subject that has been touched on here before but not resolved to my liking - this formula seems to have a huge effect on short walls when applied at a good distance from the wall. Is this really the case? I put in a wall with a 200 psf surcharge (standard for us) but now they want to put a 20' wide crane pad 8'-2" away at 1300 psf. The wall is only 7'-9" toe to top. The lateral load went from 517 lb/ft to 3378 lb/ft. I expected it to be a good bit more, but it rising linearly with the load at a distance greater than the depth of the wall surprised me.
Any thoughts?