Footings on a Sewer Line and Manhole

[tdevries37]

Hello,
I have an issue I am trying to assist my client with, who is trying to assist the GC. I designed a gas station canopy which has moment footings. They excavated the site yesterday to pour the footings and found an abandoned sewer line that will lie directly in the way of and under one of the footings. In another area, they found a manhole that will lie directly beneath another of the footings. By the way, this canopy is apparently going to sit over an old abandoned road.

My thought was to over excavate and bear the footings down farther and around the sewer line and manhole, with a minimum 6" void between the bottom of the footings and the top of the sewer line & manhole.

Any other suggestions? Thanks

 

[CTW]

Remove the abandoned obstructions.

 

[msquared48]

If the sewer line is abandoned, you should cut, remove, and plug the line with concrete directly under the footing, depending on the size.

As for the manhole, is it also a part of the abandoned sewer line? If so, rather than remove it if it's deep, you could fill it with sand partway, then the remainder with CDF.

Mike McCann
MMC Engineering

 

[tdevries37]

CTW & msquared48,

Thank you! I thought that the sewer line will need to be removed.

msquared48,

Yes, the manhole is part of the old sewer line. So if it is filled with sand & CDF, it would be OK to bear the footing directly on it, correct?

 

[msquared48]

If it is well founded into the soil matrix and shows no sign of deterioration inside. No worries.

Mike McCann
MMC Engineering