flexible pipe joints.

[newbuilder]

Hi guys,

I have another problem. We have to construct a flexible pipe joint in a pipe between a building and a manhole. The spec calls for a joint which allows a relative settlement of 200mm!!!!!!!!!!!!

Unfortunately the joints which are to be used require approx 2m of lenght to develop the movement. In some cases I only have 0.5m.

I am looking for a quality pipe joint which can take the settlement and still fit within the constraints.

Any ideas. I've already tried to move the constraints but some ae fixed.

Newbuilder [sig][/sig]

 

[prex]

I can't see any solution to your problem. Any type of expansion joint would require at least the length you quoted, as the expansion joint must be composed substantially of two hinges and a straight section in between, that has to be sufficiently long to allow for the settlement with a reasonable angle.
Could you anyway better specify your problem? I suppose the pipe is substantially horizontal and the differential settlement is vertical. Is the pipe under pressure from inside or from outside? Does it contain a fluid (moving or at rest)? Which is the diameter, thickness and material? Would it be acceptable that the pipe area is reduced as a consequence of the settlement? (thinking to some kind of sliding joint, but will hardly be acceptable).
[sig]<p>prex<br><a href=mailto:motori@xcalcs.com>motori@xcalcs.com</a><br><a href=

http://www.xcalcs.com>XcalcS</a><br>Online

tools for structural design[/sig]

 

[Ron]

I would probably go back to the specifier and question the reasonableness of this specification. When you think about it, neither the building nor the manhole can tolerate 8 inches of differential settlement, so why would one expect the pipe between to do so. I would also work on minimizing potential settlements, no accomodating them for impractical reasons. [sig][/sig]

 

[newbuilder]

Good advice chaps. Actually I also believe the settlement specified is excessive but the engineer is not backing down.

The pipe is to carry foul water under gravity only, it's 150mm dia.

Many options have been looked at, I let you know how we resolved it later - when I figure a way out.

nb [sig][/sig]

 

[Ron]

Assuming you can't get the engineer to consider reason, then what about connecting several flexible couplings together to become the pipe? Obviously this will only work with flanged connections but you might affect a solution with a combination of the this technique and other connections. [sig][/sig]

 

[Qshake]

Check out some suppliers of seismic couplers for pipe. I know its not the application you're looking for, but some of these couplers have large displacements demands.

I'm sorry I don't have a list handy... [sig][/sig]

 

[n3rei]

Hi!
I think I have a solution for you.
First the pipe is gravity only
second the pipe will carry drainage only
third the pipe needs allow 8&quot; of verticle movement over time
forth the pipe outlets into a manhole

solution:

breake opening in manhole at settled elevation minus slope invert.

place flexible poly pipe between building and manhole.

This pipe moves with no problem

One consequence is to place pipe in a chamber and not against ground since no pipe is going to push the earth between the building and the manhole down 8&quot; to compensate for the grade change. In other words the pipe will have an upwards humb basically 1/2 way tthrough if it can not push the soil down accordingly.

The chamber can be concrete covered trench, just wide enough for the pipe with a supporting structure half way through that allows a short seqment of the flexible pipe to move vertically down.

Hope this helps you.

The pipe is readily availble flexible drain pipe in the States.

Choose a sturdy type and make sure the walls of the trench are smooth to prevent nicks.


[sig][/sig]

 

[expert]

good idea i might try that!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[expert]

try using sum trditional plasssy straws!!!!!!!!!!!!!!!!!!

 

[newbuilder]

n3rei,

Great idea, thanks. Is the poly pipe ribbed (like a subsoil drain)?

Unfortunately we decided to bite the bullet and make room for the
chambers. It caused a good deal of inconvenience but perhaps is the better solution.

Thanx for all the tips.

nb