Hello,
I am in need of repalcing concrete-filled steel lolly columns in my basement. I have put 2 supports in the area of the damaged colums. One support is an expanding tubular column and the other is a PT 6×6 and ACME threaded house jack. I have been taking up on the house jack slowly over the last month andhave gotten to the point where the expanding post has gotten loose.
My question is whether the best way to proceed is to remove the damaged column and then locate the new lolly adjacent to the removed one but on, not in the concrete footing (using a steel locator plate top and bottom to eliminate any sliding potential).
I am asking because I do not know how difficult it would be to fully remove the part of the column remaining in the footing.
I have to do 2of these replacements.
Any help you can provide is greatly appreciated.
Regards.
Replies
You may try asking this on the "Breaktime" forum. Your plan sounds fine to me, but there are otheres at "Breaktime" that know a lot more than I do. You might be able to score the steel part of the column with a sawsall or even a pipe cutter (like used for cutting soil/vent stacks in plumbing) then smack it with a sledge hammer to crack the concrete fill.
Ditto on "Breaktime."
Are the existing "Lally" columns sitting on a concrete footing and surrounded by a concrete slab, or is the footing exposed? How were they damaged?
Since the old columns should be on or near the top of the footing, it shouldn't be too hard to get them out. Use a cold chisel (safety glasses!) or rent an electric jackhammer. If the hole bottom is uneven, smooth it off with mortar before setting the new columns.
Al Mollitor, Sharon MA
Thanks for a quick response. The posts are sitting on a thick footing. The balance of the floor was poured upto the level of the footing but not over the footing. I have a feeling you are right about not a lot of embedment of the column in the footing.
The columns were damaged by rusting from the inside out. The water table in the area is high and i think the concrete in the post has wicked the moisture up the column and over the years(50) has corodded the steel tube. I have the new columns and intend to protect the bottom end with a sealant to help slow down the re-occurrence of the problem. I was also thinking of using an angle grinder to score the sleel accurately before I trim off the concrete; then apply a steel top plate and drive the column upright with light application of a sledge. I estimate that the column is about 1/8 inck longer in the diagonal than the floor-to-beam length and will account for that once I know where the bottom of the column will be.
There are special tube cutters for cutting Lally columns, but since I only do a few every now and then, I use an abrasive carbide blade in my Sawzall to cut through the steel and then snap the concrete. If you only have to trim 1/8", an angle grinder might be fine.
I usually use a small hydraulic jack to lift the beam just enough to slip the column in place. A little persuasion with a hammer and block is OK, but you don't want to pound too hard, as this can deform the column and send vibrations upstairs.
After the beam is lowered, the column is securely locked in place.
Al Mollitor, Sharon MA
Al, thanks again for the quick response.
I have been using a house jaack with a 1-1/2" ACME thread for the heavy lifting since I don't have a hydraulic jack. I was able to get the expanding post thaqt was next to the lolly to become loose indicating that most of the load was off. I want to score and cut the old column and then try to remove the section that's in the footing. I like your thought that once free of the overhead carrying beam that the column most likely won't have too much of a hold in the footing. Then I can reposition the column in the old hole get the column tight on the beam and re-apply the load.
Thanks again for the help.
There are a couple of methods you might use to remove the old column. It sounds like the load is off now, so maybe the old column is not filled to the very top with concrete and maybe you can just saw it off at the top and remove. You are probably correct about the water wicking up the inside of the pipe and your situation is probably a classic show of why steel columns should not be filled with concrete. You could also just add an adjustable screw jack column next to the existing and leave the old one in place. If you want to assure yourself that the new column will not slip on the footing, just drill anchors into the footing thru the bottom plate of the column. If you are worried about moisture in the column, just drill a small hole top and bottom on the side for slight air flow to keep it dry inside.Good luck, sounds like a fun project.
I like your approach... now lets see your departure.