I had experience with $15K of Sika products last summer on a concrete wall pour “gone bad”!
Could you elaborate on that story?
I had experience with $15K of Sika products last summer on a concrete wall pour “gone bad”!
Could you elaborate on that story?
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Replies
Rez,
For a large portion of 2008 I was the owner's on site observer&project manager for the construction of a branch bank by a local design build corporation.
The plan called for a seismic rated basement pour with 10" x 10 ft walls, lots of rebar and a 4" wide x 12" stem wall top. The day was warm and forecast to hit the low 90's with a 10-15 mph wind on a very dry site.
The concrete contractor was not well prepared for his pour as 5 of the 8 9 yard mixers arrived as the concrete pump fired up and the first bit of mix hit the forms after the engineer confirmed the slump of 5". Very soon the concrete contractor stopped the pump as the concrete was not moving through the opening of the forms due to the amount of rebar and the narrow opening.
The carpenters quickly built a hopper box for the top of the forms, but that still was difficult and the contractor once again called a halt to the pour and came to the pump and asked the engineer to "give a little on the slump". The engineer asked the truck driver for his load mix sheet and asked the contractor why he called out 1" aggregate instead of a smaller rock and why no additives to allow the mix to flow.
Deer eyes in the headlights......the contractor had misread the specs and did not know what an "additive" was or what it would do. He could have used 3/8" chips as long as the mix met the break tests as well as a "flow" additive.
The contractor forged ahead and worked his men hard for 3 hours to make the pour in 4 lifts around the building ~32'x~60' with several offsets. The last lift was left to the workers/laborers as the concrete contractor owner left the site for the local tavern.
Three days later the interior forms had been removed before 10 AM and the "honey combs" parged before I made the site that day. I requested no more parge until I saw the pour as it was when the forms were removed. I went to meet with the bank CEO and to call the architect's engineer.
I returned with camera in hand, and saw the exterior walls were horrible. I called a "stop work" ---no more parge to be applied. A lot of harsh words followed. The photos of a really bad pour went to the architect. Verdict...extensive areas of unconsolidated concrete.
The concrete contractor wanted to total removal/demo of the whole basement. The general asked the engineer for his proposed fix, which was to chisel out the bad areas and patch with Sika 123 primer and fill with Sika-Flex. Lots of bitchin & moanin by the concrete contractor but the general held the purse strings.
Three demo hammers, 3 laborers, 2 masons and I spent three weeks on that basement.
There were places where the demo hammers would pierce the portland skin of the wall and then the 1" aggregate would pour out like gumballs out of a vending machine.
The demo lines would follow the cold joints of the lifts. In six areas the demos would yield a hole in the 10" wall, the smallest being the size of a big mans fist. My instrument of torture was a geologist's hammer that was used to sound-out every sq/ft of the walls.
The engineer would allow no additional loading on the structure until all repairs were complete. The framing package and floor trusses were already on site.
The cost of the Sika products was $15K and the final cost of the "patch" labor and inspection services, totaled $41K. The original bid amount on the wall was $67K.
...............Iron Helix
Ah yes, branch bank construction, I know it well. And i have had one experience with a design-build gc, but in this case we handed them stamped drawings from an architect with instructions to "build it like the plans". Even so, they tried to apply their own design-build skills at every opportunity. It was a battle.
Sounds like your gc was incompetent. Someone should have listened to the concrfete sub when the forms were removed, and just demo the whole thing. Would have been easier and faster, better results."Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Fast-EddieAnd supposedly the concrete contractor's insurance would have covered it!The bank plans were done by an independent architect in north Illinois which was the saving grace with several issues and the D/B General........Iron Helix
I had one recent project, not with the D-B gc, supposed to be about 11 mo project came in exaclty 9 mo late. What a mess. He was in over his head and would not admit it."Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
...and then the 1" aggregate would pour out like gumballs out of a vending machine.
dang man, not much to add to that visual.
and now you know why I get paid the big bucks.
yep, you guys will bring a whole new perspective everytime I fire up my clanky old Sears and Robuck cement mixer.
we are doing basically the same thing within a hour, but we use all the addition I can get. Its 97 degrees, concrete will be pushing 100 if I dont do anything. so we are batching with ice. a concrete rodeo and guess who the clown is
We had a local branch bank build project adjacent to one of our home sites here in California. In the early stages of wall construction (all poured concrete) we noticed one corner had extra thick walls and enough steel that it almost didn't need concrete for structural equivalency. Just prior to pour, my curiosity got the best of me and I had to get up close with the rebar, it was a very tight squeeze to just get your arm through the bar spaces. They came in with a crane to set the door frame for the vault and poured the next day. Even if someone were to attempt to cut through, there were electronic sensors inside the pour to detect any vibrations...just in case someone tried. It probably cost as much for the vault as it did for the rest of the building walls.
We stopped doing cast in place vaults many years ago. No benefit to that style. The slab is a little thicker (min 12", some people insist on 18") with 3 or 4 layers of #5 bar 6" oc each way. the vault is modular, precast panels about 24-30" wide with angle iron corners that get welded together. there is something in the concrete that is resistant to cutting. "Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Hey, Eddie,
Just curious, what's a pre-cast bank vault go for these days ? Door and all ? And what does that sucker weigh ?
Two local stories - about twenty years ago, the parking lot at out 1930's C & S National Bank building caved in after a very heavy rain. Turned out that some out of town n'er do wells had rented a historic old mule barn at the back corner of the bank. They had spent weeks tunnelling to just under the vault. They had moved a huge volumn of dirt, and apparantly were just before busting in from underneath, when the rain did them in. As far as I know, they were never caught. True story.
Second tale, across town, the same bank closed a branch and built a new building on a less trafficed corner - they sold the old branch to Eckerd Drugs to be torn down. Lord, they hammered at that vault for days and days and days. Some sort of jackhammer bit on a dang excavator is what I remember. The percussion would jar your teeth, and it went on and on and on. Thought they'd never clear that site - and the vault was all that was left when they tore the building down.
Oh, yeah, third story - our Chamber of Commerce is in an old circa 1900's bank building downtown. Lots of marble, probably on the Historic Register. Modern vault inside, and when the Chamber took the building over, they found out it would br prohibitively expensive to demo the old vault. Guess where the head man's office is ? Yep, and a big old stainless steel door, too.
Greg
Your second and third stories are the reasonm we use modular vaults. And why the first story is flawed. I believe the part about the tunnel, but the bad guys would have spent weeks and made lots of noise trying to break through the floor slab."Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt