Waterproof connection between concrete riser and pipe?

[Hydrostru]

I am designing a 10' by 10' by 7' high concrete riser which will be connected to a 5' concrete pipe, as an outlet for a pond. The riser is cast in place around the pipe and riser walls will be 8" thick, do I need to provide some waterproof method around the connection between the riser and pipe? I was thinking to pour flowable fill around the connection or apply "second Water Proofing Method" around.

Any help will be appreciated!

 

[PEinc]

I would say yes. You don't want the pond to drain out due to a subsurface leak between the riser and outlet drain pipe.

http://www.PeirceEngineering.com

 

[cvg]

Cast in place / embedded sounds like a good connection method. The likely scenario for a leak is differential settlement. Either the pipe or the riser settles, causing the rigid concrete connection to crack. Heavy reinforcement or flowable fill might help both the pipe and riser to move in unison, however wouldn't that just cause leakage at the next pipe joint over? Note that the pond will not "drain" through such a leak, however it could find a path to daylight along the pipe and potentially cause a piping failure. Suggest a filter diaphram or encapsulating the pipe all the way to the outlet with a granular free draining material, filter matched to the surrounding soil. This might be useful to handle any leakage and prevent piping or erosion of soil along the outlet pipe.

 

[BigH]

Maybe you might consider using Hydrotite around the pipe when you place the concrete - this offers a waterstop connection.

 

[beej67]

If it's a free standing outlet control structure be sure and do a buoyancy calculation to make sure the thing won't float off the pipe when the pond is full.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[Hoagie]

I'd consider a waterstop ('dog bone') cast in the connection and environment-friendly sealant.

 

[dik]

I've used epoxy and sand to coat the pipe and cast it into concrete or concrete 'patch' and then used a silicone caulk around the outside for good measure and not had a leak yet

Careful bedding is also prescribed...

Dik

 

[Dozerman56]

Specify either a rubber boot or N -lock gasket. Then pack the joint with hydraulic cement.

 

[3feethighandrising]

How much water is being detained? From the size of the structure, it looks like alot. Does this require a dam permit due to the volume of water detained? The dam permit safety requirements may dictate the pipe connections and pipe fittings used.