Sawcut Joint in Thickened Edge Slab
Sawcut Joint in Thickened Edge Slab
(OP)
Hi all,
I'm working on a project in which the client is proposing to excavate under a portion of the outside of an existing 8" reinforced slab structure with an edge thickened to 18" for 42" and tapered back into the slab at about 45 degrees. Piles are included at 20' O/C to support building columns. The drawing notes construction, expansion, and sawcut joints. The expansion joints are detailed with fiber board and sealer through with reinforcing steel continuous. Construction joints are not detailed, but I assume they're the same as expansion joints without fiber board/sealant and with a shear key. Sawcut joints are not detailed, but in the 8" slab I'd assume dowels mid slab and a cut to 2" and discontinuous top reinforcing steel (and maybe bottom??). Dowels at sawcut joints are noted.
What I'm struggling with is sawcut joints parallel to the thickened edge within the thickened edge. I've attached an image showing the detail and the sawcut is shown as a dashed line through the whole thickened edge. I'm presuming this would look like a 2" or so saw cut with discontinuous top bars and dowels roughly 4" under the top of the thickened edge while mid and bottom layers are continuous. I would think it's crazy to sawcut through as the line is shown. Can I get "reinforcement" or alternative thoughts on my assumptions.
Thanks in advance for any input.
I'm working on a project in which the client is proposing to excavate under a portion of the outside of an existing 8" reinforced slab structure with an edge thickened to 18" for 42" and tapered back into the slab at about 45 degrees. Piles are included at 20' O/C to support building columns. The drawing notes construction, expansion, and sawcut joints. The expansion joints are detailed with fiber board and sealer through with reinforcing steel continuous. Construction joints are not detailed, but I assume they're the same as expansion joints without fiber board/sealant and with a shear key. Sawcut joints are not detailed, but in the 8" slab I'd assume dowels mid slab and a cut to 2" and discontinuous top reinforcing steel (and maybe bottom??). Dowels at sawcut joints are noted.
What I'm struggling with is sawcut joints parallel to the thickened edge within the thickened edge. I've attached an image showing the detail and the sawcut is shown as a dashed line through the whole thickened edge. I'm presuming this would look like a 2" or so saw cut with discontinuous top bars and dowels roughly 4" under the top of the thickened edge while mid and bottom layers are continuous. I would think it's crazy to sawcut through as the line is shown. Can I get "reinforcement" or alternative thoughts on my assumptions.
Thanks in advance for any input.
RE: Sawcut Joint in Thickened Edge Slab
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RE: Sawcut Joint in Thickened Edge Slab
I agree.
The entire design looks "odd".
Piles beneath columns that bear on an integral thickened slab on grade?
Saw cut joints though a reinforced concrete slab on grade?
Expansion joints with rebar continuous through the joint?
Maybe I don't understand the description...
I would stay away from this project, if that is an option. No matter what you do, if there are (unrelated) problems you will get the "blame".
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RE: Sawcut Joint in Thickened Edge Slab
RE: Sawcut Joint in Thickened Edge Slab
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Sawcut Joint in Thickened Edge Slab
1) The construction was completed in the 1990's. Our scope is to provide recommendations on how to successfully excavate a portion of the slab to maintain services under the slab without risking maintenance personnel safety.
2) Definitely a slab-on-grade, and not structural slab. Although I agree it has atypical reinforcing for a slab-on-grade.
3) I agree the jointing is odd, but it was done in 1990.
4) These folks deserve a competent engineer to make informed decisions for their maintenance personnel. So I'm not going to decline them.
Unless there are more comments or opinions then I'll travel down to the site, dig out some joints, and report back.
RE: Sawcut Joint in Thickened Edge Slab
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