The worst concrete pour in the history of mankind!!!
I have now officially been the bad guy on a bad jobsite. Really, really bad guy.
So this project I'm working on starts off as a handoff from the guys before us, and it was a joint Army/Air Force effort. The AF guys did the design, and I was working a whole lot of other issues, and said to myself, self, the AF is a professional, technically competent outfit, they have a handle on things, don't worry about checking the design. It'll be fine.
It's an 8' foot tall concrete culvert headwall design for a bridge. There are 2 3' diameter pipes running through the headwall. Everything was approved by my predecessor. The 642nd EN CO (horizontal) will be doing the earthwork behind the headwall, the 375th EN CO (vertical) will be constructing the forms and placing the concrete.
The 375th is a reserve unit from Alabama that consists 90% of people from nowhere near AL that happen to have the right MOS for the job. There is a CW2, 1LT, and SFC in the platoon, and 4 or 5 SSGs. Everyone has been "doing this for years as a civilian." The unit has been together for all of a month or so in Wisconsin, and all their training focused on military tactics, nothing to do with building things at all.
So night one they start building. Morning one I come by and look at the forms. It looks like it's a nice start on a frame and rebar cage, though the ties are a bit messy, spacing is rough, and the development length is almost non-existent. It's only a start.
I go down to the platoon, and ask when they plan on putting the rest of the steel in. They say, "Oh, we're 90% complete, we're just going to put a few more spacers in and then we're ready to pour."
My jaw almost dropped. I said, "Uh, no, it looked like you were about 30 percent complete, we need to take a look at this." So off Chief L, the PLT technician, and I go to look at the form. I point out the lack of development length, the single bar running between the two pipes (one #6 bar and 5 inches of concrete holding up a hole roughly 7 feet wide, and 15 feet of compacted earth on top...), the...the... wait a sec, I didn't notice this earlier. There's 5 inches between these pipes. Not only is this extremely unstable structurally, there's no way in hell the compaction foot will get in here. No way in hell. We need to tear down this entire form and start over boys. Now the PL and XO show up. After hearing, "Won't the packing above this work?" and "Can't they just pack it with a Wacker?" (which we don't have and wouldn't have fit anyway) they agree the form needs to come down. And get redesigned.
At this point, my ACI code is locked in a trunk in a connex on a ship in the middle of the Atlantic. Or Indian. I don't have a GPS locator on it, but I don't have it. I don't have TCMS on my computer. I can't even pull a design from a can on this if I did. I'm going to have to design this headwall...from memory. Oh shit.
So.... I have #6 bars. Just #6s. Hmmm.... I remember 2" of cover when concrete is exposed to earth. Sounds like a good rule of thumb anyway, we'll go with that.
How thick should the section be.... 25 foot of earth (turns out it's only 16 after we got the surveyors down from Balad, thank God!) about 130 pcf (the proctor hammers and sieves are in the connex with the books) mmmmmmm.....I don't even know what my concrete strength is.... (we've got test cylinders, my 21T is going to crush them tomorrow, praying to God). So: to recap, unknown soil height, weight, concrete strength, rebar strength. I don't even know how wide the ditch is. My guys on the recon failed to bring a tape measure. Oh hell, let's make the back section 12' across and 8' tall. That's three sections of plywood stacked together. It'll have 90 degree corners. We'll make the back wall a foot thick, make the outside walls 8" thick. Space rebars 16" on the back wall, second thought, better make it 12. Hell.
How do we get steel around the holes? They only have a manual bender that does 1" radius curves at 90 degrees. Shit. Hell. Ass.
So suffice it to say, it's an ugly, ugly wall. There's 28 inches between the holes now. There's a two very beefy sidewalls. There's a metric asston of steel in it. I had an epiphany at 1 in the morning the day before the pour (also the day of the reframe) that when they pick up the thing with the crane that there will be a boatload of downward stress on the footer (as thick as a 2x10....) and there had better be some well-developed tension bars on the top of the section, or the thing will snap-crackle-pop and be one big useless paperweight in the battalion area, and I will be out of a job.
I also remembered we needed lift points at the corners, and told them to double the bars.
So the thing is finalized, and looks as good as it's gonna get, and here comes the concrete. We staged 2 pours, since there's no other way to keep the concrete from coming out of the walls with what we have than setting the base first. Here comes the concrete, yay. It goes in the base! It looks like pretty good concrete. Wait, I don't have a slump tester! Shit!
I whip out my pocket knife, and cut the top and bottom off a water bottle, and a nearby sliver of wood. I scoop some concrete in, and wiggle it out. I get a 2" drop out of 6" of bottle. Rough math gives me an equivalent 3-6 inch slump. Close enough, we'll keep it! Then the concrete starts curing. It gets noonish. I look out at the concrete, it's been an hour, and the concrete is already drying out. Shit. I grab water bottles and start dumping them on the concrete. I call down to the platoon and tell them to come dump water on the forms. And continue for 2 days. Oh, and they had to add in the horizontal bars on day 2, so they were all walking on the curing concrete footer. Yay.
And then the concrete shows up day 3 for the walls. I take a look at the forms, the braces, and my eyebrows raise a bit, but hey, the squad leader's "been doing this for years as a civilian, never any problems," and I've never done anything with forms. I remember there's fluid pressure involved, and it determines spacing of the wales, and there's probably nail spacing involved somewhere. Oy.
In comes the concrete. This time, Red Horse (Air Force civil guys) has given us a slump tester! We have a water buffalo and buckets for water! Hooray! As they start pouring from the pump truck, I say, "Hold on, move the pump over, I need to check the slump." So the guy moves it over, and the concrete comes shooting down all over my hand from 100 feet or so in the air down the hose. The concrete is approaching terminal velocity at this point. I have bruises on the back of my hand; I'm ok. :)
The slump come in at 6.5". We're looking for 6"-4". It's a bit low, but at this point, it's close enough for government work. I make a face, and say, "Eh, it's a bit low, but we'll take it." They pour the wall. Long story short, when I calculated the volume, I didn't factor in the height of the back wall, and didn't catch it because I did it in Excel, and formula checking at 2 in the morning when you're doing design work you started at noon for a pour the next day is...well... spotty at best. We need 5 more cubic meters. The PSG jumps in the truck with the contractor and rolls off to the (on base) concrete plant.
An hour or so later, back they come. This time, we're ready for the slump at the back of the concrete mixer instead of the pump truck. Thank you SSG D. The mixer guy starts sending it out. I take a look at the concrete coming down the chute, and think to myself, "You have got to be kidding me. There is no way this much can go this bad this fast. I don't even need a slump test."
There is water pouring off the concrete. It looks more like concrete soup. I scoop in the first lift, and before I start rodding, there's water bleeding out of the bottom. Two lifts later I smile, and as I pull off the cone, it plops out like a runny clam chowder. I get a slump of 9". No way in hell I'm putting this in the form. We have to get rid of this.
SFC B, the one who made the change (Pokemon, I blame YOU!!!) says "Let it roll over 20 minutes, it'll stiffen up. Yeah, no shit. It'll start curing, that doesn't make it stronger, or me more likely to keep it. I talk to MAJ K, let him know we have to ditch the load and why. We make a hasty extension to the trash can pad. A roughly $8000 tax payer funded hasty, ugly extension to the trash can pad. Hey, it's that, or the wall collapses with a $400,000 MRAP carrying 6 Soldiers and $250,000 of equipment 15 feet down to a watery crash landing. I go with the devil I know, sort of.
Measuring the pad later, we found out it contains roughly 3.5 m3 of concrete, not a full 5. More on this later!So off I go to beg, wheedle and cajole the Turkish contractor into giving us more concrete. As long as we pay for it since we (SFC B) screwed up, they'll be happy to. Great. Ok. Give me the bloody concrete.
Back we go, and pour away! As the forms start to fill, I start to notice several things happening at once. The walls are starting to spread, the top braces are starting to lift up, and all hell is starting to break loose. Instantly, everyone who was going to be handling concrete is now nailing more boards into the forms. Concrete is coming out from the joint between the culvert and the wood. I am balancing on top of the forms (safety rails? Bah!) rodding concrete with a 12 foot 2x4, and helping guide the concrete chute, yelling at people to come help shore this mess up. The next platoon over looks at us, says, "Not my job, I'm just here 9-5 man," and goes back to messing with an air compressor.
Finally, the concrete is poured, the leaks are stopped, and the forms are holding together. Yay. It's over.
I head back to the office. CPT C stops me and asks me why I have my ACU top off. I tell him I've been pouring concrete and don't want to ruin the $40 top. He said that was ok.
CPT S stops by to talk about how the pour went, and mentions in passing she walked by when I was out getting more concrete, and saw the pump truck guy unsupervised and pouring concrete into the forms. At this point, SFC H and I did some rough calcs on the new concrete pad, and notice it's roughly 1.5 m3 short. I think there may be 1.5 m3 of shitstain concrete in one of my headwalls, and the whole thing may have to be scrapped. I don't know. I wasn't there, and neither was anyone else. CW2 L says he noticed it, and had him stop, but that was because he saw the base of the form blowing out, not because he was worried about bad concrete going in the form. He says he doesn't remember where the rest of the concrete the contractor had in the pump went. It could be anywhere.
In the pump truck guy's defense, if he let the stuff cure in his truck, he'd own his life to the company for nothing, and he had to get rid of it. Or dump a bottle of Sprite in the back. He'd have to be pretty smart to know that though. Oh well.
So I've got forms coming off tomorrow. Sigh....
My first big engineering project. Ain't she a beauty? Pictures will be posted on Facebook, for those who care and can see.
So this project I'm working on starts off as a handoff from the guys before us, and it was a joint Army/Air Force effort. The AF guys did the design, and I was working a whole lot of other issues, and said to myself, self, the AF is a professional, technically competent outfit, they have a handle on things, don't worry about checking the design. It'll be fine.
It's an 8' foot tall concrete culvert headwall design for a bridge. There are 2 3' diameter pipes running through the headwall. Everything was approved by my predecessor. The 642nd EN CO (horizontal) will be doing the earthwork behind the headwall, the 375th EN CO (vertical) will be constructing the forms and placing the concrete.
The 375th is a reserve unit from Alabama that consists 90% of people from nowhere near AL that happen to have the right MOS for the job. There is a CW2, 1LT, and SFC in the platoon, and 4 or 5 SSGs. Everyone has been "doing this for years as a civilian." The unit has been together for all of a month or so in Wisconsin, and all their training focused on military tactics, nothing to do with building things at all.
So night one they start building. Morning one I come by and look at the forms. It looks like it's a nice start on a frame and rebar cage, though the ties are a bit messy, spacing is rough, and the development length is almost non-existent. It's only a start.
I go down to the platoon, and ask when they plan on putting the rest of the steel in. They say, "Oh, we're 90% complete, we're just going to put a few more spacers in and then we're ready to pour."
My jaw almost dropped. I said, "Uh, no, it looked like you were about 30 percent complete, we need to take a look at this." So off Chief L, the PLT technician, and I go to look at the form. I point out the lack of development length, the single bar running between the two pipes (one #6 bar and 5 inches of concrete holding up a hole roughly 7 feet wide, and 15 feet of compacted earth on top...), the...the... wait a sec, I didn't notice this earlier. There's 5 inches between these pipes. Not only is this extremely unstable structurally, there's no way in hell the compaction foot will get in here. No way in hell. We need to tear down this entire form and start over boys. Now the PL and XO show up. After hearing, "Won't the packing above this work?" and "Can't they just pack it with a Wacker?" (which we don't have and wouldn't have fit anyway) they agree the form needs to come down. And get redesigned.
At this point, my ACI code is locked in a trunk in a connex on a ship in the middle of the Atlantic. Or Indian. I don't have a GPS locator on it, but I don't have it. I don't have TCMS on my computer. I can't even pull a design from a can on this if I did. I'm going to have to design this headwall...from memory. Oh shit.
So.... I have #6 bars. Just #6s. Hmmm.... I remember 2" of cover when concrete is exposed to earth. Sounds like a good rule of thumb anyway, we'll go with that.
How thick should the section be.... 25 foot of earth (turns out it's only 16 after we got the surveyors down from Balad, thank God!) about 130 pcf (the proctor hammers and sieves are in the connex with the books) mmmmmmm.....I don't even know what my concrete strength is.... (we've got test cylinders, my 21T is going to crush them tomorrow, praying to God). So: to recap, unknown soil height, weight, concrete strength, rebar strength. I don't even know how wide the ditch is. My guys on the recon failed to bring a tape measure. Oh hell, let's make the back section 12' across and 8' tall. That's three sections of plywood stacked together. It'll have 90 degree corners. We'll make the back wall a foot thick, make the outside walls 8" thick. Space rebars 16" on the back wall, second thought, better make it 12. Hell.
How do we get steel around the holes? They only have a manual bender that does 1" radius curves at 90 degrees. Shit. Hell. Ass.
So suffice it to say, it's an ugly, ugly wall. There's 28 inches between the holes now. There's a two very beefy sidewalls. There's a metric asston of steel in it. I had an epiphany at 1 in the morning the day before the pour (also the day of the reframe) that when they pick up the thing with the crane that there will be a boatload of downward stress on the footer (as thick as a 2x10....) and there had better be some well-developed tension bars on the top of the section, or the thing will snap-crackle-pop and be one big useless paperweight in the battalion area, and I will be out of a job.
I also remembered we needed lift points at the corners, and told them to double the bars.
So the thing is finalized, and looks as good as it's gonna get, and here comes the concrete. We staged 2 pours, since there's no other way to keep the concrete from coming out of the walls with what we have than setting the base first. Here comes the concrete, yay. It goes in the base! It looks like pretty good concrete. Wait, I don't have a slump tester! Shit!
I whip out my pocket knife, and cut the top and bottom off a water bottle, and a nearby sliver of wood. I scoop some concrete in, and wiggle it out. I get a 2" drop out of 6" of bottle. Rough math gives me an equivalent 3-6 inch slump. Close enough, we'll keep it! Then the concrete starts curing. It gets noonish. I look out at the concrete, it's been an hour, and the concrete is already drying out. Shit. I grab water bottles and start dumping them on the concrete. I call down to the platoon and tell them to come dump water on the forms. And continue for 2 days. Oh, and they had to add in the horizontal bars on day 2, so they were all walking on the curing concrete footer. Yay.
And then the concrete shows up day 3 for the walls. I take a look at the forms, the braces, and my eyebrows raise a bit, but hey, the squad leader's "been doing this for years as a civilian, never any problems," and I've never done anything with forms. I remember there's fluid pressure involved, and it determines spacing of the wales, and there's probably nail spacing involved somewhere. Oy.
In comes the concrete. This time, Red Horse (Air Force civil guys) has given us a slump tester! We have a water buffalo and buckets for water! Hooray! As they start pouring from the pump truck, I say, "Hold on, move the pump over, I need to check the slump." So the guy moves it over, and the concrete comes shooting down all over my hand from 100 feet or so in the air down the hose. The concrete is approaching terminal velocity at this point. I have bruises on the back of my hand; I'm ok. :)
The slump come in at 6.5". We're looking for 6"-4". It's a bit low, but at this point, it's close enough for government work. I make a face, and say, "Eh, it's a bit low, but we'll take it." They pour the wall. Long story short, when I calculated the volume, I didn't factor in the height of the back wall, and didn't catch it because I did it in Excel, and formula checking at 2 in the morning when you're doing design work you started at noon for a pour the next day is...well... spotty at best. We need 5 more cubic meters. The PSG jumps in the truck with the contractor and rolls off to the (on base) concrete plant.
An hour or so later, back they come. This time, we're ready for the slump at the back of the concrete mixer instead of the pump truck. Thank you SSG D. The mixer guy starts sending it out. I take a look at the concrete coming down the chute, and think to myself, "You have got to be kidding me. There is no way this much can go this bad this fast. I don't even need a slump test."
There is water pouring off the concrete. It looks more like concrete soup. I scoop in the first lift, and before I start rodding, there's water bleeding out of the bottom. Two lifts later I smile, and as I pull off the cone, it plops out like a runny clam chowder. I get a slump of 9". No way in hell I'm putting this in the form. We have to get rid of this.
SFC B, the one who made the change (Pokemon, I blame YOU!!!) says "Let it roll over 20 minutes, it'll stiffen up. Yeah, no shit. It'll start curing, that doesn't make it stronger, or me more likely to keep it. I talk to MAJ K, let him know we have to ditch the load and why. We make a hasty extension to the trash can pad. A roughly $8000 tax payer funded hasty, ugly extension to the trash can pad. Hey, it's that, or the wall collapses with a $400,000 MRAP carrying 6 Soldiers and $250,000 of equipment 15 feet down to a watery crash landing. I go with the devil I know, sort of.
Measuring the pad later, we found out it contains roughly 3.5 m3 of concrete, not a full 5. More on this later!So off I go to beg, wheedle and cajole the Turkish contractor into giving us more concrete. As long as we pay for it since we (SFC B) screwed up, they'll be happy to. Great. Ok. Give me the bloody concrete.
Back we go, and pour away! As the forms start to fill, I start to notice several things happening at once. The walls are starting to spread, the top braces are starting to lift up, and all hell is starting to break loose. Instantly, everyone who was going to be handling concrete is now nailing more boards into the forms. Concrete is coming out from the joint between the culvert and the wood. I am balancing on top of the forms (safety rails? Bah!) rodding concrete with a 12 foot 2x4, and helping guide the concrete chute, yelling at people to come help shore this mess up. The next platoon over looks at us, says, "Not my job, I'm just here 9-5 man," and goes back to messing with an air compressor.
Finally, the concrete is poured, the leaks are stopped, and the forms are holding together. Yay. It's over.
I head back to the office. CPT C stops me and asks me why I have my ACU top off. I tell him I've been pouring concrete and don't want to ruin the $40 top. He said that was ok.
CPT S stops by to talk about how the pour went, and mentions in passing she walked by when I was out getting more concrete, and saw the pump truck guy unsupervised and pouring concrete into the forms. At this point, SFC H and I did some rough calcs on the new concrete pad, and notice it's roughly 1.5 m3 short. I think there may be 1.5 m3 of shitstain concrete in one of my headwalls, and the whole thing may have to be scrapped. I don't know. I wasn't there, and neither was anyone else. CW2 L says he noticed it, and had him stop, but that was because he saw the base of the form blowing out, not because he was worried about bad concrete going in the form. He says he doesn't remember where the rest of the concrete the contractor had in the pump went. It could be anywhere.
In the pump truck guy's defense, if he let the stuff cure in his truck, he'd own his life to the company for nothing, and he had to get rid of it. Or dump a bottle of Sprite in the back. He'd have to be pretty smart to know that though. Oh well.
So I've got forms coming off tomorrow. Sigh....
My first big engineering project. Ain't she a beauty? Pictures will be posted on Facebook, for those who care and can see.