Opening in Concrete Shear Wall
Opening in Concrete Shear Wall
(OP)
Colleagues,
I have a situation where a sizable portion of an existing concrete shear wall was removed. It seems that someone wanted a doorway and simply removed the pesky concrete that was in the way. I suppose the most direct fix would be to dowel in rebar and replace the concrete but I just thought I'd check if any of you esteemed folks might have any creative ideas for remediation other than that? Thanks.
I have a situation where a sizable portion of an existing concrete shear wall was removed. It seems that someone wanted a doorway and simply removed the pesky concrete that was in the way. I suppose the most direct fix would be to dowel in rebar and replace the concrete but I just thought I'd check if any of you esteemed folks might have any creative ideas for remediation other than that? Thanks.






RE: Opening in Concrete Shear Wall
RE: Opening in Concrete Shear Wall
I know it's easier to just repair the wall and claim "No harm, no foul", but if you can make it work, that should be your first approach.
RE: Opening in Concrete Shear Wall
RE: Opening in Concrete Shear Wall
RE: Opening in Concrete Shear Wall
If in-plane shear is not an issue because there is plenty of solid wall along that line, then your only retrofit is to check out-of-plane.
Depending on the vertical bar spacing, you may still be able to justify the out-of-plane. If not, I like to add some C8 channels across the header and at the jambs, assuming the architect can deal with it.
If the doorway added is narrow, you normally can get the out-of-plane to figure by taking a "4t" tributary of wall thickness as your new jamb.
Last check, how is the lintel? How deep is it? 18" horizontal bar spacing? If the doorway is just a single door opening, and the lintel has any reasonable depth, it normally all figures ok.
Most building codes have provisions for when you have to upgrade the building depending on how much it was modified.
I believe there may be a 5% rule for a single element, 10% for the total change in mass...I would have to look it up.
And last, normally in-plane shear is not a problem for a concrete shear wall building and I doubt the opening caused problems with that unless the wall in question already has several narrow piers and not many long walls along that line. Not sure if you're in a high seismic zone or not.. If the wall is exterior, then wind may govern seismic for low seismic zone.
RE: Opening in Concrete Shear Wall
RE: Opening in Concrete Shear Wall
Mike McCann
MMC Engineering