We poured our sonotubes the other day and put 6″x6″ post holders in the top of them. Just over 24 hours later my husband hit one with the bobcat (A good reason not to work in the dark). He hit it hard enough to bend the post holder over and loosed it in the cement.
Now I’m wondering if this kind of shock to the cement will seriously effect the cement’s strenght since it would still have been curing. This sonotube will be holding up a covered veranda. If the consensus is that the concrete should be OK, can we just add fresh mortar to the hole where the post holder came out of and try to reset, or is there some other kind of compound that you would suggest?
I should tell you that the sonotube is 3′ in hight with a BIGFOOT footing under and had been backfilled. We also have two pieces of rebar running down through the center.
Replies
I am not concrete guy but I am Home Remodeling Contractor show I will give you my suggestion. one ? how far does the sonotube measure from the ground to the top of the sonotube? if they are couple inches it should be fine. I would fill the hole with hydraulic cement or high strength concrete (depends on how deep you have destroyed), let it cure then drill - using hammerdrill for the 1/2" thread rod and epoxy.
I am glad that you are using rebar in the sonotube, most contractor do. not
Thanks for the advise. The sonotube sticks only a couple inches out of the ground. If we get rid of the loose concrete can we assume that the rest is stable?
it seems fine, but why don't you let other guys share some inputs :)
Dig next to the sonotube down to the footing, peel off the tube, examine the concrete to see if you cracked the column. If not, the column should be fine. Repair the post base as others have suggested.
Photo?
PAHS Designer/Builder- Bury it!
its no good, need to be replace
Do you figure the concrete will breakdown over time, even if it seems hard now? I don't know mcu about the curing process.
I'll try and get a picture for tomorrow.
If you can straighten out the post holder, do that. I'm assuming the concrete is not broken badly .Worse come to worse , cut the metal off flush with the top. Then epoxy bolts for a new post holder.
mike
JoeDy
Like any other loose stack of rocks, it should be ok for a relatively few freeze/thaw cycles, but I'ld replace it, myself.
Of course, when I pour piers, I'm doing it for someone else and I don't want them talking bad about me in a few years.
SamT
In the daylight we had a chance to look at the damage more closely. The cement was amost flush with the ground. So when the bobcat's tire hit the post holder it pushed it over and cause the crack to start at center and vear to the edge. We chipped away all the loose pieces. The cement around the two pieces of rebar do not apear to be disturbed, and their are no signs of other cracks.
At this point our plan is to drill down the center of the sonotube and insert a deeper piece of steal and seal it all up with apoxy. I realize that it is the cheep and easy way out and that it has the potential of possibly failing in the future. However, it is the outside corner of a veranda that would be relatively easy to excave in the future should we start to see a problem. As we are crazy busy with the house constuction now...why do today what you can do tomorrow? Just kidding, anyway thank you for all your input.
hit the post holder it pushed it over and cause the crack to start at center and vear to the edge
Ok, is this "post holder" a galvanized (flat) metal type, or a bolt/rebar anchor set in the top of the concrete?
If it is a Simpson or similar column base, then usually you can just get another and expansion bolt (or epoxied allthread) it bac one the concrete pier top.
Now, I'm guessing that you mean the concrete cracked, and that crack runs to one edge--correct?
If so, what you may need is not the advise of a bunch of guys on the internet. What you may need is the person who has to sign off on the structural stuff for this contract. Which depends on where you are, what sort of project this is, etc. (You could fill us in, at least a little bit, by filling in your profile--which the gavel-drivers have made easy by placing a "UPDATE PROFILE" in dark grey at the top senter of the screen).
Now, BB may be entirely correct. Hitting a sonotube of "green" concrete hard enough to knock anchor bolts out of kilter might have transfered that movement to the rebar, which might have moved in a good portion of their length down the columns. Ok, there's two "mights" there, so what? Well, if the bar moved, it could have made a void i nthe concrete. Rebar has to be in full contact with the bar for it to do any good. If the bar is in there because it's needed for the engineering of the piers, then the design might not meet spec (sheesh another 'might' he's killin us here).
Occupational hazard of my occupation not being around (sorry Bubba)
Another concern is whether this has opened up small gaps between concrete and steel, making it easy for water to get in, rust the steel, which causes it to expand ....
Therefore, two options:
1. Get someone who knows to look at it in person
2. Do as BB says, do it over.
-- J.S.
JoeDy,
I've seen worse things done with concrete that lasted the life of the structure.
SamT
First off, we only put the rebar in the sonotube because we had extra stuff lying around.
Second, the bracket is the kind with a rebar rod that goes 6 inches into the concrete with a metal saddle on top for a 6"x6" post to sit in. we chipped off the cracked portion of the sonotube which removed approximately, 7 inches off the top corner.
We have a concrete guy coming out tonight to have a look.
Thanks for everyone's opinions.
concrete guy not going be able tell you anything, you need an engineer. concrete guys are laborer without driver license. all they can do is finish.
Q: What do you call a laborer without a driver's licence?A: A concrete finisher.Brownbagg, that one is going to work with me today. <G>
what do you call a laborer with a driver license, a truck driver.
JoeDy,
What you have left is a pile of closely fitted stone packed in a cardboard tube.
Don't know what shapes or sizes the stones are, but probably not flat on tops and bottoms.
In order to truely know, as opposed to a sight unseen guess, what condition the pier is in, you will have to excavate and strip the sono . . . oh wait, you've excavated it, might as well replace it while you've got the hole open.
It will cost less to replace than to properly determine that it is still usable. Maybe still usable. Maybe usable with repairs. After you've excavated and stripped it.
A piers purpose in life is not just to hold things up, but to also hold them down in strange circumstance, like heavy winds. Imagine what damage would occur if your veranda was picked up and slammed into the side of your house!
On the other hand, maybe none of that stuff will happen.
Day old concrete has about the strength of dried Play-Doh. And you really whacked it a good one.
SamT
Another thing to consider if you have cracks: There's this epoxy injection stuff that's used here in earthquake country to stick old footings back together. What it's used on is usually decades rather than days old, though. Probably somebody else here knows better than I if that might make sense for your problem.
-- J.S.
You might take note of Brownbagg's post. That's what he does for a liviing is inspect this stuff, and he definitely knows his stuff.
Concrete does not achieve its strength by drying, but by curing, which is a chemical process by which crystals are formed around the sand and aggregate.
If you mechanically disturb that proces within about 3 days of the time you placed it, the concrete is junk. 5 to 14 days, it's questionable.
How long has the concrete been in place?
It has only been 3 days now. But we figured that since the rebar wasn't touched the bottom 7/8ths of the sonotube should be OK???
The bottom probably is OK, but the top is where the critical connection lives, so you can no longer have full confidence that it will always do it's own job
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
If only the top part of the concrete was damaged, you might demolish the top part, which would be quite easy as the concrete is still green. This would allow you to inspect the damage to see how deep it goes. Slip a new tube over the remaining concrete and re-pour.
take note of Brownbagg's post
Unless he was being facitious (which has been known to happen <g>)
Occupational hazard of my occupation not being around (sorry Bubba)