Split Sonotube to Install Around In-Place Bar?
Split Sonotube to Install Around In-Place Bar?
(OP)
I'm trying to figure a way to install piers between a reinforced concrete grade beam above, and competent rock below. Reinforcing for the pier will be a single number 9 bar, doweled into the existing grade beam. After the bar is in place, I will have to put the sonotube around it, and the only way I can imagine to do that, is to cut a lengthwise seam in the tube, slip it around the rebar, and then stitch the seam back together.
Has anyone seen this done? Any suggestions on ways to securely close the seam? I'm considering some kind of bands or zip ties, possibly combined with polyurethane adhesive or heavy staples.
Has anyone seen this done? Any suggestions on ways to securely close the seam? I'm considering some kind of bands or zip ties, possibly combined with polyurethane adhesive or heavy staples.





RE: Split Sonotube to Install Around In-Place Bar?
Duct tape the inside of the seam.
RE: Split Sonotube to Install Around In-Place Bar?
Where have you seen this method used?
RE: Split Sonotube to Install Around In-Place Bar?
What diameter tube are you anticipating? How are you going to get concrete into it underneath the grade beam?
Ron's method makes sense for a small diameter tube (say 6"), but as the tube gets larger, the method gets riskier. If exposure to moisture between installation and concrete placement is very likely, you might consider using PVC pipe instead.
Ralph
Structures Consulting
Northeast USA
RE: Split Sonotube to Install Around In-Place Bar?
RE: Split Sonotube to Install Around In-Place Bar?
soiset Watch out for moisture issues. Form tubes can deal with a limited amount of exposure to water (after all, the concrete is wet), but too much exposure before placing concrete will weaken them.
I think you could have an issue with reliable consolidation of the concrete underneath the grade beam. You might consider stopping the pier concrete an inch or so short of the bottom of the grade beam. Consolidate well, let the concrete cure a bit, then dry-pack the space with a very stiff non-shrink grount.
Or use a self-consolidating mix if available and fill your 'funnel' well above the bottom of the grade beam. Provide a sealable hole in the form tube on the opposite side from the 'funnel' to facilitate the concrete's ability to push out any air.
Ralph
Structures Consulting
Northeast USA
RE: Split Sonotube to Install Around In-Place Bar?
RE: Split Sonotube to Install Around In-Place Bar?
I've not used duct tape, but I've seen 4 or 6 mil plastic 'socks' placed in the sonotube to provide a smoothe surface. These can likely be held in place with a staplegun at the top.
If bearing is an issue, the space at the top of the sonotube is used as a sprue to get the concrete in with the help of a small plywood chute and then drypack the space between the gradebeam and the top of the pile.
Dik
RE: Split Sonotube to Install Around In-Place Bar?
RE: Split Sonotube to Install Around In-Place Bar?
RE: Split Sonotube to Install Around In-Place Bar?
If you plan to use normal, plant-run concrete, you may need to hold back the initial placement from the top and fill the gap after shrinkage. If you control shrinkage in the mix design and settlement in the foundation, you may be able to place all of the concrete at once, but you should probably plan on filling a gap a few days, or longer, after the pour.
RE: Split Sonotube to Install Around In-Place Bar?
The gap is left to allow for plastic settlement, not shrinkage. The same reason you don't cast a floor with the columns below.
RE: Split Sonotube to Install Around In-Place Bar?