Pipe Flange connection detail in a RCC Underground Pit

[allimuthug]

Hi, I have a underground in which the Pipe is Anchored as shown in the Figure below.

The Pit is formed by keeping a hole as shown in the elevation for pipe flange connection. Later the Pipe is installed and grouted
as shown in the elevation and section. The grout locks with the wall.
The flange cracks the concrete and if the concrete gives up in breaking it engages the re-bar which is subjected to shear.
Please correct me if I am wrong.

 

[JStephen]

First off, consider if the pipe NEEDS to be anchored at that point. It's possible to build it like that, but not a requirement where a pipe passes through a wall. I've seen a Link-Seal product specified to seal a pipe to a penetration without making a rigid connection, for example: Link

It looks to me like in one direction of force, you'd have a punching-shear problem, in the other direction, a shear-friction problem (plus plate-bending of the whole vault side). In the shear-friction case, the rebar is not just loaded in shear, but is assumed to act in tension holding the surfaces together. That implies some relative movement between them, and also implies that you have enough embedment on either end to develop the force- which looks doubtful in the sketch.

 

[JedClampett]

You and the contractor would prefer a wall fitting (they make them for DIP and steel) instead of that fancy blockout. Wall fittings can come with flange ends, plain ends, mechanical joints or a Carnegie fitting.
If your pipe has enough force that you're having problems with punching shear, you might want to check your pipe analysis. From the picture, you should have basically no force on the wall.
Or listen to JStephen and put in a penetration and seal it with link seals.

 

[thaidavid40]

If there is that much force in the pipe that it needs anchoring, you might be much better off pouring a thrust block well outside of the pit, and avoiding all that fancy, expensive detailing (which will likely fail to perform properly anyway). Then you could just use a Link-Seal and be done with it.
Dave

Thaidavid

 

[dik]

If compatible with the fluid, I like Bentonite 'rope' and give the pipe a couple of turns within the concrete.

Dik