tornado pics- masonry wall failure
tornado pics- masonry wall failure
(OP)
With all due respect to the victims of this tragedy, there are also lessons to be learned from a forensic engineering standpoint.
I have done a lot of forensic investigations of wind damage, but this is one of the few lateral pressure failures of CMU that I have ever seen (at least IMO it is). Well, I should say the connection to the roof diaphragm may have been the failure mechanism also. But there is no rebar sticking out of the wall which looks to be at least 15 feet tall! I would like to see how the wall would look with #5s at 48" oc or less.
Picture 60
http://www.weather.com/news/photos-tornado-outbrea...
I have done a lot of forensic investigations of wind damage, but this is one of the few lateral pressure failures of CMU that I have ever seen (at least IMO it is). Well, I should say the connection to the roof diaphragm may have been the failure mechanism also. But there is no rebar sticking out of the wall which looks to be at least 15 feet tall! I would like to see how the wall would look with #5s at 48" oc or less.
Picture 60
http://www.weather.com/news/photos-tornado-outbrea...






RE: tornado pics- masonry wall failure
RE: tornado pics- masonry wall failure
It's weird, it doesn't even look like there is mortar between the blocks.
RE: tornado pics- masonry wall failure
RE: tornado pics- masonry wall failure
As for this one the bricks on the ground mind indicate the direction of the wind pressures. Possibly the front wall pushed in opening up the building to positive pressure and blowing out that side wall (note the bricks on the ground). If the front wall pushed in then it was probably a combination of no reinforcement and minimal/poor/nonexistant attachment to the roof diaphragm. Either that or they cleared the bricks away from the front of the store.
Maine EIT, Civil/Structural.
RE: tornado pics- masonry wall failure
I also agree with you TME, positive pressure failed that front wall and negative (maybe combined with high internal pressures) failed the side wall.
RE: tornado pics- masonry wall failure
First link is the building. Street view will give you the elevation.
Building
This link shows the billboard over the guys shoulder that's still standing in the parking lot of the same building.
Billboard in Lot
RE: tornado pics- masonry wall failure
RE: tornado pics- masonry wall failure
RE: tornado pics- masonry wall failure
RE: tornado pics- masonry wall failure
My surprise is that this does not happen more often during actual wind events. I have done a LOT of forensic investigations following wind events, and I think all of the CMU failures I have witnessed or seen photographs of are likely initiated by a lack of support at the top of the wall (roof or floor blown away) and the CMU fails by tipping over, sometimes intact. Actual bending stress failures are rare in my experience, though in theory it should be a huge problem, other things happen to fail first (ex. windows and doors failing, letting in wind, roof fails).
I attached an example of what I mean from another tornado where it appears the CMU failure is a loss of roof support.