Sloped surcharge set back from retaining wall? 1

[kkoloj]

Are there any formulas, articles, or books, that anyone knows of for a situation in which a sloped surcharge is set back some distance from the back of a retaining wall. That is, the toe of slope does not occur right at the back of the wall.

I am civil eng. trying to write spreedsheets for the design of swimming pool walls for various loading conditions. I have found a lot of information about infinite strip loads, finite strip loads, point loads, and line loads, however I have not come across anything for the question above.

Thanks for any help.

 

[SlideRuleEra]

Here is one (manual) approach using Rankine's work:

1. Compute the pressure diagram for a level bank.
2. Compute the pressure diagram for an inclined bank with the top of the wall assumed to be where a projection of your setback inclined bank intersects the wall (assumed wall height will be shorter than the true wall height).
3. Compute the pressure diagram for this theoretical shorter wall using the math for the inclined bank assumption.
4. Overlay the two diagrams and follow the line of highest pressure for the answer.

I'm talking as if this is being solved graphically, but of course you can do it mathematically too.

As for reference for the calculations, L.B. Foster Company (a sheet pile supplier) offers their catalog on CD at this site:

http://www.lbfoster.com/piling/technical.html

The catalog contains many reference documents including "US Steel Design Extracts". One of the extracts has diagrams and equations for the two situations (level bank & inclined bank) described above. All you need to do is superimpose results from the two calcs.

I'm bet that there is software that can do this more accurately and efficiently however.

 

[kkoloj]

Thanks for the information SlideRuleEra. I will definitely look into the CD from LB Foster

 

[BigH]

There is always the Culmann graphical method that might be amenable to a spreadsheet with some keen interest. You might be able to set it up for more complex back of wall conditions. I've not tried it but it would be a challenge . . .

 

[kkoloj]

SlideRuleEra:

I received the CD catalog from LB Foster, however, the section I was most interested in, the design section, was not included in the PDF. I can see this design section in the table of contents, but the CD will not let me get to those pages. Have you had this problem?

Thanks again.

 

[SlideRuleEra]

kkoloj - I just double checked my CD and have no trouble accessing the information that I referenced. Perhaps we have different editions of the CD, mine is: "2003 Version 2.0"
Here is what works for me:
1. After loading the CD, close the window that it opens, but leave the CD in the tray.
2. Use Windows Explorer to look on the CD. Amoung other things, I see a file titled "Piling.pdf" (a big file over 387 Mb). Open this file.
3. After opening the file, Adobe Acrobat Reader shows that there are 567 pages. The information that I referenced begins on page 289.

If this does not work, and if you choose to do so, post an e-mail address and I will send you the referenced pages.

Best Wishes

 

[kkoloj]

SlideRuleEra:

OK, I will give it a try with the CD, however last night I simply did a search for USACE (which is referenced in the CD) and found the sections that I could not access.

Thanks again, I will try what you mentioned with the CD.