Cantilever Sheet Pile Seeing Surcharge Plus Strip Load

[JNEnginr]

Hey guys,

I'm really trying to wrap my brain around this. I have a Cantilevered Sheet Pile that is holding back 13ft of earth. I'm assuming soil density is homogeneous throughout and I have granular soil. I have a surcharge load and a Cooper E80 Strip load. I know that the 100psf surcharge is going to act uniformly along the sheet. I know the strip footing pressure can be found using Boussinesq Equation, but I read I can take 0.8 of the worst case pressure (for a given length and depth away from the sheet) and apply a uniform pressure along the sheet as well.

First, can anyone confirm the 0.8 assumption?

Second, does anyone have an example problem showing a cantilevered sheet pile in granular soil with a surcharge load? I'm interested to see how the pressure diagram changes when the surcharge is applied.

Any help is appreciated. I can post the 4 pages of calcs I have if needed.

Thanks,

 

[GeoPaveTraffic]

Don't know about the 0.8, never seen that.

As for E80 loading, most railroads don't allow a Cantilever sheet pile wall within the zone of influence of the tracks for any reason. I suggest you check with your cleint and/or the railroad before putting much effort into the design.

Mike Lambert

 

[JNEnginr]

Thanks for your response. Per the state's guidelines, Cantilever sheet piles are allowed if the shoring is at least 12' away from centerline of the track. I am currently 24ft away from the centerline of the track. Despite this, the influence line (1.5 to 1 slope) hits about 2ft above where I am excavating to.

 

[jorton]

Norfolk Southern allows you to design for a uniform load of 0.8 times the peak lateral load. See the following link. They have other design criteria published on their "documents" page. You will need to figure out what your railroad allows.

http://www.nscorp.com/nscorphtml/pdf/Customers/SEC3_MISC1.pdf

I would apply the uniform lateral load down to the toe of the sheet. It is additive to the pressures acting on the "pushing" side, so you will have to extend your toe for the statics to work out.

 

[JNEnginr]

How do I find the area of Area 7 and Area 8 individually? I can find the combined area of 6 7 & 8 by taking the areas of A1-A-F-A2 + JCE - A1-E-A2.....But how does that help me? In the end I need to calculate the moment arm of each area about F. Am I missing something stupid?

 

[califdirtguy]

Google - slideruleera.net and look for out of print publications - you will find a PDF copy of USS Steel Sheet Piling Design Manual
(February 1974) - This could help you in understanding one of the processes. You can find a copy of CalTrans Trenching and Shoring Manual Revision 12 at vulcanhammer.net, this also might help. Happy reading and learning!

 

[RFreund]

I can't get to my website right now, but I should have some notes on this and link to the California T&S manual (an older addition which is helpful for hand calcs) if you look there. I must say I really should update that page and will in the near future.

EIT

http://www.HowToEngineer.com

 

[JNEnginr]

Thanks for everyone's responses. I found an example calculation in the Foundation Engineering Handbook by Manjriker Gunaratne. There they simplify the passive and active shapes, but I must say I really don't understand how they do so.