retrofitting a steel post in a basement
retrofitting a steel post in a basement
(OP)
ok folks. One story house, wood framed floor, slab on grade. I'm going to have them cut the slab and pour a new footing, and install a new steel post to replace a jack post that has failed by crushing the wood. How do they get the perfect length for the post, and then install it so that it's flush? Without the jack action, I'm worried there would be a gap or it would be impossible to actually install. Thoughts?






RE: retrofitting a steel post in a basement
RE: retrofitting a steel post in a basement
If possible, I would use a couple of side plates welded to the plate too to nail off the to the beam, and a couple of vertical tabs to nail off to the column - something like a Simpson CC hanger sized for the wood members.
Mike McCann
MMC Engineering
RE: retrofitting a steel post in a basement
RE: retrofitting a steel post in a basement
RE: retrofitting a steel post in a basement
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: retrofitting a steel post in a basement
Just replace the jack with a wood column - 6X6, 6X8, 8X8 or whatever you need.
Mike McCann
MMC Engineering
RE: retrofitting a steel post in a basement
That looks like a real cobbled mess. Joists over cut at their notches, so they could fit over 2x2 ledger strips; then the double or triple 2x beam partly saw cut through, for some reason, and then cracked off to the right. You’ll have to kinda determine the magnitude of the loads on either side of that saw cut through the beam, and you’ll want to balance those loads over the steel cap system I’m going to suggest and over that existing jack post, repositioned a few inches to the left. You are going to have to do some jacking and temp. shoring to lift everything off the post as it is. I would take a 6" or 8" channel, legs down, for some strength about its weak axis, about 3' or 4' long, from a steel suppliers cut-off pile for least cost; centered under that balance point, and on the axis of the existing 2x beam. Put a few struct. screws through the Cweb and up into the 2x beam, near its ends. I’m not thinking any sort of a moment connection here, just a flat bearing surface, with some bending strength, and some resistance to rotating if your balance point isn’t perfect. Then, use a .5"+ pl., 12" long and just wide enough to fit btwn. the C radii for your repositioned jack post cap pl. over its existing light cap pl. This is just to spread the post load along the length of the channel a bit.
You’ve see this before in some of your old books on timber mill buildings, where they had a large timber column, then a cap timber (corbel timber?) over the column and immediately under the primary beam timber. You might also want to take a look at the IBC or IRC, there is considerable debate about those jack posts meeting code if the pipe walls are too thin, or if the screw jack is not disabled or embedded in the conc. when you are done. And, that the light cap pl. must be nailed off so the post can’t be just pushed over, or unscrewed.
RE: retrofitting a steel post in a basement
boy am I ever glad for this site, to bounce ideas around.
RE: retrofitting a steel post in a basement
If you want the steel column instead of wood, just weld a pipe column to a Simpson CC (without the side tabs to the column) .
Mike McCann
MMC Engineering
RE: retrofitting a steel post in a basement