The hydrostatic pressure of that concrete, assuming normal wet ready mix is roughly a bit under 300lb/cubic foot and what looks like about a 4 foot depth, would be 1,200lb/square foot, so in just the 20 feet we can see in this gif there was almost 24,000lbs pushing out against the base of that wall. Clearly a bit more than the resisting force of the mass of the CMU and soil friction. Our boy's lucky he didn't kill someone.
I can't tell you how many times I had to listen to the phrase "I'm not an engineer, but (fill in some ridiculous structural or site related statement here)"
I understand that Engineers are overpaid dumbasses that don't know which end of the nail to bang on. That is, right up until your job blows up in your face because of an amateur mistake like this. Then it's "You're the Engineer, not me."
There's a cantilever retaining wall already designed for every height and every soil type already, all you need to be able to do is look it up in one of the many handbooks. If you really want a segmental block design, the supplier will happily do the design for you.
But this guy apparently knew better, and soon after this was recorded, he was on the phone with his insurance company, if he had one.
I suspect that guy's troubles are only beginning. The loss of lateral support can cause the area he is standing on to start to subside. This is a strict liability situation. Not a lawyer, not providing legal advice. However, that dude is fooked. You are right that a number of pre-approved designs already exist. Looking at the guy, he does not appear to be the sort who knew that.
The term you're avoiding is "tie-back" and it can be done several ways, none of which appeared to be happening in that gif. Yes, I'm an engineer with very long experience.
Can't tell what kind of footer the block wall was sitting on, but one thing is for sure, there was no vertical reinforcement rods in place and the CMU hadn't been filled before hand. Also no kind of horizontal reinforcement either.
If the concrete is too dry, you may get a lower pressure on the form, but you will have other problems in exchange. About a 3" slum is right, but your forms have to be braced properly, and a CMU wall is not an adequate form. I would not trust it even if the voids are filled and you use rebar.
I suspect that even with the right "slump", the concrete would have still pushed the wall over because of no kind of horizontal or vertical reinforcement. Even just some block wire every couple of courses would have helped hold the wall up. It wasn't that high.
#10, the truck should not have been there in the first place. Things like that can happen anytime you are lifting a load. It appears the cable may have been a bit worn.
#1, whoever the captain was, he allowed his boat top get too close to shore, and crossways with the swells. Judging from the sail he was close to being in irons and wasn't getting much effort.
#7 looks like about my first time at Golf. My SoCal city has a city golf course and gave free lessons to minors, which I took. I finally had to give up Golf as one of my knees are too bad to play even after I have had a Doctor work on it.
That’s not the first time that kid has swung a golf club. He went too far on his backswing and tried to crush the ball but if he keeps practicing he’ll have one hell of swing one day.
$5 says that when they were cleaning up they filled the dishwasher with Palmolive (or some such), turned it on then went out for coffee. That reminded me of the video of the numbsculls that were trying to figure out how to fill up their Tesla tires with LP.
#1 - If only they had a couple of 300hp Yamaha outboards... #3 - As a Phillies fan... Love it! #5 - A block wall has huge compressive strength - very little lateral... Dude should have known.
Dur-o-Wall? They sell many CMU masonry products but I don't think any of them would have prevented that disaster. Durawall is a product for leaking foundation walls I think.
#5 +1000 OOOOOOOHHHH Fudge moment !!!
ReplyDeleteThe retaining wall needs a retaining wall needs a retaining wall . . .
DeleteUnbraced forms will do that sort of thing.
DeleteWorst possible scenario, truck in #10 belongs to the city inspector or OSHA inspector.
ReplyDelete"YOU'RE THE INSPECTOR! You should know better than to park there!
DeleteBoth inspectors and quality control folks are known for parking in the middle of everything. Without fail.
DeleteThe hydrostatic pressure of that concrete, assuming normal wet ready mix is roughly a bit under 300lb/cubic foot and what looks like about a 4 foot depth, would be 1,200lb/square foot, so in just the 20 feet we can see in this gif there was almost 24,000lbs pushing out against the base of that wall. Clearly a bit more than the resisting force of the mass of the CMU and soil friction. Our boy's lucky he didn't kill someone.
ReplyDeleteI can't tell you how many times I had to listen to the phrase "I'm not an engineer, but (fill in some ridiculous structural or site related statement here)"
I understand that Engineers are overpaid dumbasses that don't know which end of the nail to bang on. That is, right up until your job blows up in your face because of an amateur mistake like this. Then it's "You're the Engineer, not me."
There's a cantilever retaining wall already designed for every height and every soil type already, all you need to be able to do is look it up in one of the many handbooks. If you really want a segmental block design, the supplier will happily do the design for you.
But this guy apparently knew better, and soon after this was recorded, he was on the phone with his insurance company, if he had one.
I suspect that guy's troubles are only beginning. The loss of lateral support can cause the area he is standing on to start to subside. This is a strict liability situation. Not a lawyer, not providing legal advice. However, that dude is fooked.
DeleteYou are right that a number of pre-approved designs already exist. Looking at the guy, he does not appear to be the sort who knew that.
Everybody rags on engineers until they do something stupid that an engineer wouldn't have done.
DeleteThe term you're avoiding is "tie-back" and it can be done several ways, none of which appeared to be happening in that gif. Yes, I'm an engineer with very long experience.
DeleteI want to see what the professionals say about 5). I know someone here has done this kind of work.
ReplyDeleteI did that work in a past life.
DeleteWithout more information, it would be hard to give specific answers
Can't tell what kind of footer the block wall was sitting on, but one thing is for sure, there was no vertical reinforcement rods in place and the CMU hadn't been filled before hand. Also no kind of horizontal reinforcement either.
DeleteI suspect that the pour MAY have been ok if the the concrete hadn't been so wet.
DeleteIf the concrete is too dry, you may get a lower pressure on the form, but you will have other problems in exchange. About a 3" slum is right, but your forms have to be braced properly, and a CMU wall is not an adequate form. I would not trust it even if the voids are filled and you use rebar.
DeleteI suspect that even with the right "slump", the concrete would have still pushed the wall over because of no kind of horizontal or vertical reinforcement. Even just some block wire every couple of courses would have helped hold the wall up. It wasn't that high.
Delete#7--Kid was giving it his all.
ReplyDelete#10-Boss pissed him off?
Midwest Chick
#10, the truck should not have been there in the first place. Things like that can happen anytime you are lifting a load. It appears the cable may have been a bit worn.
Delete#1, whoever the captain was, he allowed his boat top get too close to shore, and crossways with the swells. Judging from the sail he was close to being in irons and wasn't getting much effort.
Delete#7 Great coil!!!
ReplyDelete#7 is why I do not golf
ReplyDelete#7 looks like about my first time at Golf. My SoCal city has a city golf course and gave free lessons to minors, which I took. I finally had to give up Golf as one of my knees are too bad to play even after I have had a Doctor work on it.
ReplyDeleteThat’s not the first time that kid has swung a golf club. He went too far on his backswing and tried to crush the ball but if he keeps practicing he’ll have one hell of swing one day.
ReplyDeleteI keep lookin at it, but.....what the heck is goin on in #2?
ReplyDeleteIt appears as if they put an electric kettle on the stove and the plastic on the outside caught fire.
DeleteRegardless, it's not supposed to do that.
$5 says that when they were cleaning up they filled the dishwasher with Palmolive (or some such), turned it on then went out for coffee. That reminded me of the video of the numbsculls that were trying to figure out how to fill up their Tesla tires with LP.
Delete#1 - If only they had a couple of 300hp Yamaha outboards...
ReplyDelete#3 - As a Phillies fan... Love it!
#5 - A block wall has huge compressive strength - very little lateral... Dude should have known.
It wouldn't have mattered how strong that wall was in any direction. That is a sliding failure, in this case catastrophic sliding failure.
DeleteDurawall helps.
DeleteDur-o-Wall? They sell many CMU masonry products but I don't think any of them would have prevented that disaster. Durawall is a product for leaking foundation walls I think.
Delete#6 is what you get for using electrical appliancess in what appears to be a camping tent.
ReplyDelete