How would you remove a concrete pier?

[grampastractor]

I need to remove a 6' high 18" thick concrete pier. I have been told that it may be 4' in the ground and is in the center of a 12' square concrete pad that is about 6" thick. To complicate things, it is close to a building and the pad is part of the building.
This is left over from an observatory that was attached to this building. I would like to save the pad if I can and the building!
I was thinking of cutting the concrete 3' from the building and breaking out the rest and renting a hoe to dig out the pier, hoping not to damage the building in the process. I would then need to pour a new pad.
Any better ideas?
Thanks
Don va3any

[Brad_Blazer]

Use a demolition hammer to remove the concrete around the base, exposing the rebar, then cut the rebar to remove the column. Chip the concrete away to just below the surface of the pad then trowel some new concrete to smooth it out. A concrete saw might work even better. An engine hoist should work to handle the column as it is cut. The part below ground: leave it.

[grampastractor]

Use a demolition hammer to remove the concrete around the base, exposing the rebar, then cut the rebar to remove the column. Chip the concrete away to just below the surface of the pad then trowel some new concrete to smooth it out. A concrete saw might work even better. An engine hoist should work to handle the column as it is cut. The part below ground: leave it.

I do not know if it has rebar or not, if not your idea would be even easier. I am just concerned about supporting the concrete column while cutting, when it lets go it will go fast and hard if I don't have it held well enough. Do you think an engine hoist would hold it? I moved a smaller one with the tractor bucket and it seemed like a good load.
Thanks for the help.
Don va3any

[vtsnowedin]

Assuming your pier is round the six feet above the floor level weighs 1600 pounds. I'd second the jack hammer and concrete saw method but get a hold of it so it can't fall on your foot. Chain wrapped around and hooked to a good sized loader bucket if you can drive to it or block and tackle, come-a-longs or chain-falls if you can't.

[bcp]

Any better ideas?

Pillar crane:

[90cummins]

I removed an 18”x18" pier for my chimney using the 3pt hitch on my (small) 650 JD tractor.
First I dug around the pier and down a foot or so I could get a choker chain around it then I attached it to my 3pt hitch and attempted to raise it.
It was quite secure but I slowly moved the tractor back & forth (at idle) several inches or so while applying constant up force.
The constant lift and the rocking slowly pulled the pier up. I had to choke up on the pier a couple times to finally get it completely out of the hole.
It would have taken a huge amount of force to just pull it straight out but rocking it back & forth loosened the soils grip on the footing. It actually came out easier than I thought.

[chim]

Concrete is roughly 150#/CF. I figured your 18"ﾘ x 72" pier is less than 1,300#. We handle concrete cylinders on a regular basis. We have an order now for some that are 24" in diameter and up to 10' tall. We lift them using three different methods:

1. Almost all have bolts protruding from the end and start life upright. If we simply want to move them and keep them upright, we have a steel plate with a lift point that gets bolted to the cylinder and we use an overhead crane.

2. When we want to load them on a truck, we choke them with a heavy fabric sling. It is not going to slip as fast as a chain may, and choked about 1/3 down from the top it allows for a smooth transition between vertical and horizontal.

3. We store some cylinders. For that, they are rotated to horizontal using the OH crane and then carried with a yardlift to be placed on 4x4 cribbing (think big tractor with a forklift where the 3PH should be).

At work we do everything we can to comply with safety rules because we don't want to have someone get hurt. Good chokers in like new condition are the best way to lift the loads we are involved with. The only chains we use for lifting are those manufactured with rating tags and they must pass regular inspection (as does all our lifting equipment).

[Brad_Blazer]

I do not know if it has rebar or not, if not your idea would be even easier. I am just concerned about supporting the concrete column while cutting, when it lets go it will go fast and hard if I don't have it held well enough. Do you think an engine hoist would hold it? I moved a smaller one with the tractor bucket and it seemed like a good load.
Thanks for the help.
Don va3any

You can use your tractor bucket. Keep vertical tension on the column. Assuming it has rebar, leave 2 intact on the side closest to the tractor to act as a hinge and lower the column as you back away. If you are attached near the top you will never have to support much more than half the load or about 1000lb. After it's down cut the remaining rebar. BE AWARE there will be some spring-back in the bent rebar. If there was something mounted on top of a free-standing column it almost certainly has rebar.

[Egon]

If you had some therma cord it would get easier!

But in reality try the jack Hammer. Cut a square on the pad around the pier so the finishing is easier.

[grampastractor]

Thanks everyone for the ideas. Looks like breaking/ cutting the pier off is the way to go. I am still a little worried about my tractor being able to control it when it snaps off and I don't think my wife will let me use it as an excuse to buy a bigger tractor.
Thanks again.
Don va3any