Jesse Boring wrote:
1. At about 24" water started slowly seeping into the holes. Some of the holes are filled up to the 24" line if left overnight. I'm worried about that weakening the concrete mix but I'm going to use garbage bags for my belled out footers anyway so I guess this will be ok? I wonder if that fact that I hit water so quickly means that digging a shallow well might be possible later on in the project. Anybody have any thoughts? It did rain a few days before I was digging, not sure if that my influence what I'm experiencing.
That rock is a great foundational support mechanism, I don't see any reason to remove it.
Jesse Boring wrote:2. I hit a huge rock on one of my piers. The thing goes down about 8 inches and bisects the hole. The bottom is at least 3'10" below grade so I'm thinking that I'll just pour around it since I can't seem to get through it. I'd be very interested in thoughts and advice about this.
You certainly may be right about your concerns. I think my fallback, if things start to go horribly wrong down the line, will be to create a dry stacked stone foundation underneath the piers and then cut the piers out from the process completely.
If you have a moment I'd be curious if the idea of putting in a french drain relieves your concerns at all?
1. My sono tubes are 48" long and my tallest pier will be 84". I'm planning on keeping the tubes 12" off the bottom of the pier so I'm missing about 24" of height for my tallest piers. Can I tape the tubes together and/or splint them in some way? I worry about them not staying in a straight line if I do that. Some of my tubes nest within each other even though they're all nominally 12" diameter. Maybe I should nest them to make a longer tube? Just curious if this is a normal issue or if I just need to source longer tubes somewhere.
2. How much do I need to worry about wet weather? I'm assuming rain is fine for the curing concrete (though probably not so good for the concrete still in bags) but will the sonotubes hold up to rain for 48 hours or so?
3. Does 3 days seem like a reasonable time frame for pouring 12 piers. I'm going to have to relevel my batter boards and redo my grid since I put those too close to my piers and wound up knocking them around as I was digging.
Ap - 0 to 10 inches: channery silt loam
Bw - 10 to 17 inches: channery silt loam
E - 17 to 20 inches: channery silt loam
Bx1 - 20 to 49 inches: very flaggy silt loam
Depth to restrictive feature: 14 to 26 inches to fragipan
Natural drainage class: Moderately well drained
Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately high (0.00 to 0.20 in/hr)
Depth to water table: About 12 to 19 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: Low (about 3.5 inches)
I was referring to the total height (minus the footer) of the piers when I was referring to 84". The highest piers will be 36" above grade, with the middle piers being about 24" above grade. Do you think it will help at all to put extra pieces of rebar in the piers on the high side?
...build up the middle of the footer a bit with gravel or cobbles so that the foot has slightly concave shape. He said that this was done on the footers for sky-scrapers and that it would give extra stability...
I had been planning on putting the bottom of my sonotubes 12" above the bottom of my holes because that's generally been suggested in the things I've read about it. However, it would be a lot easier for me if I could bring them up a bit higher, say 24 or 30 inches above the bottom, to cut down on the number of times I'll have to splint two sonotubes together to get to my final height. Anybody have thoughts and/or experience with that?
ay, I haven't been doing a slump test, I'm hoping to go by the feel/sight (as well as the recommendations for the amount of water). Admittedly that has made things a bit dicey but the cones don't seem to be readily available to buy (for today) so I think I'll move forward without using the slump test. Just to double check, when you say "fully wetted" do you mean that the color of the concrete has all chanced from light gray to dark gray and is damp, with no discolored patches, or do you mean everything should be in a slightly liquid form?