Concrete Retaining Wall Design 1

[otto_eng]

Hi,

I'm EIT working in a structural engineering/design office. I'm trying to understand how to start designing a concrete retaining wall. Since the wall is acting like a C shape concrete member which is loaded from all three sides by the soil, I'm confused if it is logical to design the walls as separate cantilevered retaining walls. I feel like I'd over design if I design them as separate cantilevered retaining walls.
I'd be happy, if I can get brief explanation about this matter.
Thank you in advance...

 

[JGard1985]

Please don't double post,

http://files.engineering.com/downlo...95b7e0&file=Retaining_Wall_Design_Example.pdf

Jeff
Pipe Stress Analysis Engineer

http://www.xceed-eng.com

 

[otto_eng]

Thank for it Jeff but my question is not about how to do design a separate cantilevered retaining wall.

 

[MotorCity]

I assume by "C shape", you mean it is C-shape in plan. Assuming the soil, loading, and geometry are all the same for each portion of the "C", you can design a single wall and use that same design for all 3 sides. Otherwise, you would have to design each side separately. I would tie all 3 sides together with corner bars.

 

[SlideRuleEra]

I'd be happy, if I can get brief explanation about this matter.

The corners will proved some support to the wall... but at what distance from the corner does this extra support "go away" - therefore requiring the wall to be designed as if it is "infinitely long"?

Don't try to fine tune design of a retaining wall. There are too many unknowns (e.g. exact soil properties, drainage from backfill behind the wall, possible unexpected surcharge on the backfill).

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[bootlegend]

I would look at the tables in PCA publication "Rectangular Concrete Tanks" or "Moments & Reactions for Rectangular Plates" by W.T.Moody. These give coefficients for shear and moment based on wall geometry and edge conditions (fixed, free, pinned). You can quickly get an idea if it's worth trying to design it other than pure cantilever. I've designed a couple like this and the free edges of the C have always been similar to the pure cantilever. The "middle" wall will benefit from the extra supports at the edges if the span is not too long, but it quickly approaches the pure cantilever condition if I recall correctly.

 

[rapt]

A dimensioned diagram would be really useful. The answer depends a lot on the actual layout, and we have no idea what it is.