Sheet Pile with Sloped Dredge line

[ahunt]

Good Day!
I'm in charge of designing a small section of steel sheet piling in sandy soils. To date, I've been able to complete the hand calculations based on foundation text by DAS. Very nice proceedures that my reviewers can follow.

The problem comes in with the dredge line. It slopes away at 2 horiz to 1 vert from the sheeting. I will also need to calculate deflection at the top of the sheeting. Anyone have any good books to recommend? I'm not as worried about this one problem as I am the education in what is out there.

I've looked at some documents such as the Army Corps of Engineers design manuals, but not much luck. Bowels suggests a finite element based proceedure, but I sure would like hand calculations if possible.

Is this normal that structural engineers design sheeting? Seems like a geotechnical problem to me, but that's not what my company has ever done.

Any comments would be great!
Merry Christmas!

 

[PEinc]

Try using Coulomb's equations for Ka and Kp with sloping ground in front of and behind the wall. You can also conside using wall friction with Coulomb's equations. A downward sloping surface in front of the base of the wall will reduce the passive earth pressure coefficient.

Either a geotech or a structural engineer can do the number crunching design (if they know how). However, you should get guidance fron a geotech on the earth loads, surcharge loads, and soil properties such as unit weights, friction angles, and cohesion. Especially get help if the wall needs tieback anchors.

 

[DRC1]

Pilebuck used to distribute a pile design handbook. There was a limted release of the e-book version of the updated manual, but I am not sure where to find it now. However the orginal bible is the US Steel Sheetpiling Design Manual, which I believe can be found on Slideeruleera's website. This will take you through step by step several different designs for bulkheads. As for lateral pressure, I generally use C&K (log sprial)method, which can be found in table form in the design manual. This allows for sloping dredgelines and backfills. There are many ways to calculate deflection, all are very approximate. An easy and generaly suitable accurate method is to apply all the active loads to the sheeting that occur above the point where the net pressure move from the retained side to the dredged side. Generally this is about 5 feet down. Then just treat it as a cantilevered beam at the point of zero net pressure.If you have a simple shape, such as a triangular soil load, don't worry about the redued pressue between the dredge line and zero pressue. Just continue the shape to the end of the cantilever and use simple formulas to solve. Remember, deflection is an approximation. Not many people take the time to do hand calculations any more. I applaud your efforts to take the time to learn this the old fashion way and truely get a feel for the analysis.

 

[ahunt]

Thanks for all the information. I see Slideruleera has great information on the website.

It's too bad we are so dependent on computers that we can't complete the calculations without them.

I'm also reviewing the AASHTO bridge manual. I see they touch on the sloped dredge line concept.

A.

 

[PEinc]

Pile Buck is supposedly back up and running. They are offering a revised sheet pile design manual on CD. Check Pile Buck's web site.

 

[PEinc]

http://www.pilebuck.com/