Concrete Tank Installation
Concrete Tank Installation
(OP)
We are currently in the construction phase of a wastewater treatment system. We have a tank being installed that has 7 reinforced concrete sections with vertical joints. At two of the joints the contractor is unable to push it home, leaving roughly a 2 inch gap all the way around. The water depth in this tank will be approximately 7 feet. The manufacturer is acknowledging it is most likely due to cold temperatures, but claiming that because the gasket is fully seated it is a non-issue. They are proposing to finish by filling the gap with a hydraulic cement. Is there anything else I should consider and would this be common practice? Thanks.





RE: Concrete Tank Installation
Push what home?
The manufacturer of what? The concrete panels?
What does the contract say the contractor has to do?
Is this a design problem or a "field" problem?
What is the role of the "manufacturer" in this contract? Will the manufacturer "sign off and hold harmless" in this situation. Maybe even post a guarantee bond?
RE: Concrete Tank Installation
RE: Concrete Tank Installation
Hint: Multiply concrete thermal expansion coef x delta T (outside temp - daily average temp) x length of each concrete section. It will not be 2 inches, will it.
RE: Concrete Tank Installation
This sounds like some kind of proprietary tank system. I've seen hundreds of tanks, and never heard of anything like this. Assuming it is round, what resists the hoop stresses? Or if it is rectangular, there's big corner stresses. If it needs a lock between sections and they don't meet up, you've got an issue.
Some prestressed tanks are made of precast walls, but those are tensioned and shotcreted after the panels are put up.
RE: Concrete Tank Installation
RE: Concrete Tank Installation
RE: Concrete Tank Installation
Well in cold weather the concrete sections will shrink (contract) a bit, which makes the problem worse, but! - that contraction is not 2 inches. Think bridge expansion joints - they are not 2 inches in 50 feet, right?
So, what are the dimensions of this rubber gasket? 4 inches wide? 3 inches wide? Will the weather (once the project gets finished) ever get colder than it is right now?
RE: Concrete Tank Installation
RE: Concrete Tank Installation
How can hydraulic cement engage the seal fingers?
RE: Concrete Tank Installation
RE: Concrete Tank Installation
RE: Concrete Tank Installation
RE: Concrete Tank Installation
You should contact the manufacturer and follow his instructions. Otherwise, you warranty will be void. Contact the engineering designer at the home office.
The manufacturer should have tolerances for this type of error.
RE: Concrete Tank Installation
RE: Concrete Tank Installation
Also, if you were to accept the use of the hydraulic cement, I would require them to use it on both sides of the gap, not only one like you showed in your picture. Also, you might have curing problems if it's too cold.
RE: Concrete Tank Installation
RE: Concrete Tank Installation
the drawings do not indicate that a 2 inch gap is within tolerance, so why would you accept some on the fly fix? this is a recipe for disaster. reject it outright and require correct fabrication and installation
RE: Concrete Tank Installation
Can you lubricate the bell end of the joint to help with the pressing/fitting action of the tendons? Is the outside of the tank frozen to the ground that it contacts? Is the open joint which is not visible filled with soil from the pushing/fitting process, thus preventing proper fit-up? Build a heating tent, 3'-4' on each side of the joint and completely enclosing the tank walls at the joint. Heat this for a few days to heat the concrete and to warm and soften the gasket. That should prove or disprove the manufacturer’s theory about it being to cold. I’ll bet that part of their sales pitch is that their tanks can be installed in any weather conditions. So now, put-up and shut-up Mr. manuf’er. The transfer of any loads, particularly relative lateral loads btwn. the two tank sections, any differential settlement or soil or hydraulic lateral loads, is dependant upon that joint being fully seated. Otherwise, you are trying to transfer these loads across fairly thin cantilever sections which are now much longer that the original design contemplated. Of course, water tightness is important too. If they can’t pull this together with the tendons, then get some hydraulic jacking equipment to help push on the free end of the last section.
RE: Concrete Tank Installation
Steve
RE: Concrete Tank Installation
RE: Concrete Tank Installation
RE: Concrete Tank Installation
RE: Concrete Tank Installation
RE: Concrete Tank Installation
RE: Concrete Tank Installation
You may need to use some hydraulic or screw jacks to spread the pinch points so the gasket joints will push home.
RE: Concrete Tank Installation