Double Wythe CMU Retaining Wall

[Ridgeng]

I am being asked to VE a tall (12') concrete wall that is a retaining wall first and then a tall concrete building foundation wall that will be tied into the slab as a metal building will be built on top of the foundation wall. To achieve this a double wythe will be required. I searched this site for tips on how to make the two layers act together and found one from 2003. The member dutchie indicated there was an article indicating what the unit ties should be but does not indicate what the article is. Does anyone have experience in doing a two wythe (8" each wythe) retaining / tall wall to point me in the right direction.

 

[phamENG]

You want to look at TMS 402 sections 8.2.6.1 or 9.1.7 depending on what your design methodology is. If you just have two wythes next to each other, you have to determine the shear stress at the interface that allows them to act compositely. If you can't get that to work with mortar, I'd suggest just turning every course. And even if you can show that the first way works...I'd still have them turn every other course. You won't use any more material, and the wall will be stronger for it.

 

[JLNJ]

They make some block larger than 12". You might look into it rather than using two wythes.