GRP Concrete Structures Pipe Interface

[stanier]

I am ooking for reference with practical examples of the interface between GRP piping and concrete structures.

Piping will be up to DN2000.

Structures could settle or lift (expansive clays).

GRP is recognised as having low strain tolerance and hence the details of entries into concrete tanks, sumps through floors or walls is critical.

 

[bimr]

See page 21 in the engineering guide:

http://www.smithfiberglass.com/pdf/E5000.pdf

 

[bimr]

See page 6:

http://www.ameron-fpg.com/files/pdf/FP278.pdf

See page 4:

http://www.pipexcompositepipes.co.uk/download.php?id=6&type=TECHDATAPDF

 

[civilperson]

Flexible couplings at exterior connections is standard in California below grade utility entrances to buildings.

 

[stanier]

Civilperson,

How do you achieve a flexible joint in aburied situation?

If backfilled then the flexibility is compromised. If in a concrete pit then building is allowed to move ralative to the pit? If so what is the interface between pit and building such that strain is not applied to te strain limited GRP?

Are the details published of this type of connection?

 

[stanier]

bimr,

I am well versed in these techniques. The detail covers minor movements between structures. The challenge is that the use of O ring joints requires thrust blocks. At DN2000 these become very large masses. The thrust blocks themselves are likely to settle differentially to the pipe and thus cause high local strain on the GRP.

 

[civilperson]

Reference the seismic retrofit of the San Francisco Courthouse. The flexible connections were in a air space between the basement walls and exterior retaining walls, (like a moat).

 

[bimr]

Stanier,

What you seem to be looking for is the same technique that is used on plastic tanks.

Plastic tanks squat when they are filled. The squatting will cause the piping connections to fail.

What is typically recommended is to not pipe directly into the tank. Change piping direction with an elbow several feet prior to entering the tank.

 

[stanier]

Bimr,

If you have an inground structure and there is bottom entry the structure can move relative to the pipe and cause strain. The elbows will be buried and not provide the protection required. Bringing the pipe above ground affects the hydraulics and thus energy consumption.

We are talking up to DN2000 here.

Really what I am looking for are technical papers, books or other references that cover large bore GRP pipe connected to structures that may move differentially to the piping.

 

[dicksewerrat]

They make a 'rubber' connector to go from pipe to manhole. The Manhole side has internal stainless expanding band and the pipe side has external bands. It tends to reduce leaks at manholes.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com