masonry retaining wall - reinforcing

huangyhg

masonry retaining wall - reinforcing ?
i am designing a 12' high ret. wall.  the block's f'm=2000 psi.  it's 12" retaining wall block which is the type with grooves cut into it for horizontal reinf.  my reinf. steel's fy=60ksi.  i called out for #8s @ 8" for vert. reinf. 3" from the soil side.  the contractor wants to use a lesser bar.  i have the horizontal reinf. i can tie to.  anyone see a problem with calling for (2) #6s in each cell at the same location as the original w/ 3" between them?  i am using special inspection and am going to make them tie to the horizontal steel to maintain this distance
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if the reinforcing is lap spliced, which it will likely be  for a 12 foot tall wall, you could have a few cells with the equivalent of 4-#6 bars in a cell.  add this to any hozizontal bars you may have in the grooves, and it doesn't leave a lot of room for grout!
in my opinion, using (2) #6's in a core is difficult.  with 12" cmu, the cores are about 6" x9".  trying to get grout arond a single bar in a cmu wall is difficulkt.  trying to get grout around (2)#6's vertical + (2)#6 dowels or splice bars will be next to impossible.  stick with the #8's
better yet, switch to a concrete wall, you will probably cut the reinforcing steel required by a 1/3.   
definitely keep it to a single bar per cell for ease of placement and grouting purposes.