||01-29-2013 11:48 PM
I have used rebarr in them to make them sturdier, but it's pretty overkill. I did it because I was worried about the ground getting soft, so I used a hammer drill and drove 4 10 foot piecs 3/8 rebarr into the bottoms of the holes angled out and then bent them together straight up the center and poured the crete around that.
As for reinforcing the concrete itself no worries it is great plenty strong enough. If you have a really wet area where the soil get mucky two or three feet deep you might consider the rebarr to make the piers more stable. Driving the ten foot rebarr's seven feet in at a 45deg angle into the bottom of the hole and bunching them together in the center will keep a building standing in the worst of sloppy soil.