Friday, September 14, 2007

RE: Retaining Wall Questions

On 13 Sep 2007 at 17:56, Wesley Werner wrote:

>
> Jordan,
>
>  This doesn't exactly answer your question, but at a seminar I
>  attended on segmental retaining walls the
> presenter said that you had to design the walls as one wall unless the
> horizontal distance between them was at least twice the height of the
> lower wall. He didn't give us the theory behind the rule-of-thumb,
> though. Also, he said that you needed to check the global stability of
> the whole tiered system. He said that he had seen at least one case
> where a whole hillside gave way behind the walls rather than the walls
> themselves giving way.
>
>
> Wesley C. Werner

Hello,

I've bolded the last two sentences in the above quote, because it touches
on what I was going to say about these designs.

Global stability is part of the reason for the setbacks and not just to
develop the passive pressures.  Checking the overall slope stability is
a very important thing.  If the slope failure plane in below all of your walls
and daylights on the downhill side of your lowest wall, then you risk
having the whole thing come down walls and all.

Check the slope and make sure that you've extended the wall below
that slip plane, and designed for the loads that the slope may impart
to the wall if/when it tries to slip.

Take Care,
Lloyd