Masonry wall and foundation stem wall construction
Masonry wall and foundation stem wall construction
(OP)
I am designing a masonry addition that is sitting on a concrete stem wall. The masonry is fully grouted with vertical bars spaced 32" o.c. I can't space the stem wall vertical spacing that far apart because of the concrete minimum spacing requirements. So with my masonry bar spacing @ 32" o.c. and my concrete stem wall spacing @ 18" o.c. they won't ever meet up. I could reduce the spacing in the stem wall to 16" o.c. to lap with the masonry wall spacing and need to so it is an 8" increment. Is there any reason why I need the stem wall bars to lap with the vertical bars in the masonry? The bars coming out of the stem wall provide shear resistance at the base of the wall for out of plane and in plane forces. The vertical bars in the masonry wall are developed enough past the midpoint of the wall and shouldn't need to be lapped with the stem wall bars. I realize my stem wall spacing needs to be at 8" increments but other than that if every vertical bar in the masonry wall doesn't lap with a bar in the stem wall is this really a problem or is it just good practice?






RE: Masonry wall and foundation stem wall construction
I would field bend the bar slightly or locally slightly chip out the intermediate rib if the bar hit a rib to get the bar into a cell, or just abandon the bars where they hit the intermediate CMU ribs if the shear from the other bar connections is sufficient.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Masonry wall and foundation stem wall construction
RE: Masonry wall and foundation stem wall construction
RE: Masonry wall and foundation stem wall construction
RE: Masonry wall and foundation stem wall construction
RE: Masonry wall and foundation stem wall construction
Hokie.... I don’t know where the terminology ‘stem wall’ came from, maybe a short stem on top of the footing. Usually, the term ‘stem wall’ connotes a shorter height wall on top of a footing, as opposed to a full ht., story high, found. wall as in a full height basement. The stem wall may have soil on both sides as with a slab on grade; or only on one side as with a crawl space under the first fl.; often with lighter rebar too. Our footings are down at 48" for frost cover, so we commonly have a 3 or 4' high stem wall up to the sill plate or slab on grade. You see some wild variations of ‘stem walls’ when you get in the DIY’er. and small home builder arena.
RE: Masonry wall and foundation stem wall construction
I could do that, its not that big of deal. I gave some rebar spacings, but my question was really more about if the rebar really needed to be lapped or not. If my stem wall spacing was 24" o.c. and my masonry wall spacing was 32" o.c., then it may be more of an issue.