Catch Basin Repair

[sjp8]

The contractor damaged the knockout for a catch basin during installation. Short of making him replace the structure. Can anyone come up with a solution to repairing the oversized irregular knockout hole or know where a detail might exist?

The catch basin is proposed to have a 12" RCP pipe outlet. I was thinking drill 6" on center, the circumference of the opening and bend in some # 2 or # 3 rebar vertically and horizontally into 2 inch deep holes. Holes would be cleaned and Epoxy would be used in all holes. We could use 4x4 or 6x6 9 gage wire mesh to cover the rebar. At the circumference of the pipe, we would bend a continuous full length # 3 rebar approximately 3" in from the pipe to tie the ends of the vertical and horizontal tails and then place 4000# concrete to 3 ft out of the pipe for the collar, around the pipe and fill the existing void. Rod the concrete to consolidate then rub smooth and place bituminous coating 20-30mil thick when cured 3 days. Protect with 15# asphaltic paper and then backfill at 5 days.

I am open to any other suggestions and would very much appreciate any feedback.

Thanks.

 

[cvg]

seems a little extreme for a catch basin. How do you normally connect the pipe into the knockout - just drypack mortar? 4,000# concrete for the collar also seems like overkill to me. Contractor may rather replace it then do all of this.

 

[CarlB]

"seems a little extreme for a catch basin."

Agreed. Isn't a catch basin merely for transitioning a vertical hole in the ground to a horizontal hole?

 

[sjp8]

Thanks CarlB and cvg. Perhaps you are right.

I may be overthinking it.