Ground water seepage into the wet well of wastewater pump station 4

[NADOR123]

Hi everyone,

During the installation of pre-cast concrete wet well, the joint between the base section and the ring above had been damaged.

The wet well is in ground water and there is ground water seepage into the wet well after the installation. I was looking at some concrete repair products but I wander if anyone has other suggestion to provide repair method more effective and permanent other than just patching the leaking area. The problem is that the leaking joint is below the inlet pipe and once the wet well become online it is not possible to find out if there is a leak or not.

The wet well is 8 feet Diameter and 15 feet high and max. ground water elevation is about 8' from the grade elevation

 

[civilperson]

Line exterior walls with bentonite filled boards. Patch interior with polymer concrete and then line with glass reinforced plastic, (epoxy is best).

 

[Prepakt1]

Just grout the space between the precast and the soil. If there is no space do some permeation grouting. Expensive but would fix the problem. There is also coatings like
HLM 5000 which would provide a waterproof barrier.This stuff sets up really hard and waterproof.

Intrusion Prepakt /marineconcrete.com

 

[bimr]

Whether the wetwell is repairable, depends on the extent of the damage. The first call should go to the manufacturer of the precast section. The precast section is a manufactured product and should not be repaired without the consent of the manufacturer. Otherwise, you void the product warranty.

You should contact the manufacturer of the precast section and obtain repair procedures. My understanding is that ASTM Standard Specification No. C 478, Section 9 has procedures for repair of precast sections.

Any manhole products exhibiting imperfections in manufacture, damage during handling or other damage should generally be rejected

Field repairs should only be allowed if the repairs are very minor and do not affect the structural integrity of the manhole. The manufacturer of the precast section would have to quantify the extent of the damage, particularly if there is structural damage.

 

[bpattengale]

As a side note check the specifications for the project. Our specifications have a provision in them stating
"Broken or cracked pipe, mislaid pipe and other defects shall be corrected."
and
"All repairs, relaying of sewers, ect. required to bring the sewers to specified status shall be made at no additional cost to the Owner or the Owner's representative."

If this is a sanitary lift station as it sounds like from your original post it should also be required to pass a leakage test. Obviously it would not pass this test.

Since the wet well does not meet specification (Our specifications at least) and was due to installation error make the contractor remove and replace the wet well or if the damage is very minor allow a field repair. Finally any repair or replacement should be at no cost to the owner since the contractor damaged the pipe during installation.

 

[LCruiser]

The cost, unless T&M, should be on the contractor. You definitely need the mfgr's okay on the repair. Excavating to see the exterior is going to be expensive. Maybe you could pressurize the interior (plugging the pipes of course) and inject some epoxy - just coating the inside if the pressure is greater on the outside won't work with anything *I* know of. It needs to get through the joint and not just be a surface patch.

 

[Ussuri]

Its not that big a wet well. You could tank it externally.

 

[mrglobal]

Just like everyone is telling you get the Mfgr's okay if you dont youcould open yourself up to some major problems in the future.