Slip Lining - Culvert Rehab Discussion

[civilman72]

I've tried to search the forum but supisingly haven't found a lot of discussion regarding culvert rehab, at least not the with people's experience of product issues after construction has been completed.

The agency I do engineerng work for is considering slip lining numerous CMPs that are under large fills (>10') and I've been tasked with researching options and costs. The choices are endless, and the products salesmen all proclaim their products work. But considering the lack of history for the majority of these remediation options, it's easy to be skeptical.

I spoke with a local DOT hydraulic engineer who has lots of slip-lining experience. He is having lots of issues with expansion/contraction of the HDPE lining pipes and he's concerned with the long-term integrity of the culvert and surrounding grout. He stated these culverts were connected with the concrete headwalls by removing the outside liner and allowing the concrete to tie-in with the culvert corrugations, which is the method that the manufacturer's rep states stops the culvert from moving. He is now experimenting with allowing the culvert to "float" and not require a tie-in to the headwalls.

I'm in a very cold region of Colorado, so temperature fluctuation is a major design concern (80 deg. (F) in the summer and as cold as -30 deg (F) in the winter).

Anybody have experience with success/failures of culvert rehab projects? Specific discussion of slip lining would be helpful, but I would welcome comments on all types of culvert rehab options. Thanks!

 

[civilman72]

cvg: I've looked into Hobas pipe. Main concerns are the costs and it's (evidently) more susceptible to abrasion, which is an issue in one of the creek crossings we are analyzing. But the more I discover the possible issues with HDPHE, the more desirable an FRP becomes.

SMIAH: I agree that the strength of HDPE pipe is highly dependent on proper compaction around the pipe. One of our rehab projects has a 60' fill, and I would anticipate that HDPE wall thickness would have to be increased to accommodate this surcharge. Not sure if it would affect the grout application.

Dick: Any experience with longevity of CIPP applications? That is my biggest concern.

I greatly appreciate everyone's input.

 

[dicksewerrat]

We really don't know how long CIPP liners will last. Some liners installed in the late 70's were dug up and retested for physical properties. They tested out at the installed tests. The Trenchless Institute at Louisiana Tech is trying to get some samples of old liners to do a study. I haven't heard how successful they were at getting any.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[cvg]

from what I can tell, HOBAS would be just as resistant to abrasion than typical CIPP or possibly more so since production is controlled in the factory rather than inside the pipe and aggregates are used. longevity of the CIPP depends on the materials used eg (glass-fibre, needled felt, resin and PE coating - most do not have aggregates as found in Hobas).

http://www.hobas.com/technology/centrifugal-casting.html

 

[civilman72]

Dick: I know that CIPP has been used in sewer pipes fairly successfully, going back 20-30 years. But its use in large storm pipes appears to be more recent. I will do some research on TTC @ LTU.

cvg: I was specifically comparing the abrasion resistance between HDPE and FRP. I agree that CIPP probably has the lowest of the three, particularly the resin and felt materials.

Thanks.

 

[SMIAH]

Back on the DOT Engineer who has lots of slip-lining experience.

How can he fill the voids with the grout without a tie-in at the headwall?

 

[civilman72]

SMIAH: My understanding it that the grout is still held in place with a bulkhead during the initial pour. The differenc being when the headwalls are poured they do not remove the outer skin of the pipe, which exposes the corrugations and allows the headwall concrete to tie-in with the ends of the pipes.

 

[Twinkie]

Thanks for this discussion, it has given me an option for a culvert replacement we are doing in the Spring. Due to design constraints, we are having a difficulty matching the existing cross-section area of (2) 41" x 72" CMP arch pipes. While we are very confident we do not need all that capacity for the existing stream, permitting a culver with reduced capacity is a headache, as you all know.

I'm going to do my research now, this may be a real cost savings for us, as well as an ease on the permitting.

 

[dicksewerrat]

Twinkie,
There is a new method for the design of that shaped pipe. Called 'Thepot' or French method . We have been lining those types of pipes for a while now. about where are you located? we are on the East coast, northern VA.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[Twinkie]

This project is in SE PA

 

[SMIAH]

@Twinkie: You may be able to perform sliplining of an arch culvert too.
There might be an option with a pipe-arch CSP (Aluminized, Polymer-Laminated).

 

[Twinkie]

We are looking at all options right now, as this is the last piece in a road project that begins construciton today. It is just such an odd size CIPP sounds like a very reasonable alternative to replacement with a box or slip lining. We do not have much cover over the cluver ~2 feet so going to larger capacity rounds is not an option. Our analysis of the watershed justifies an actual reduction in culvert capacity, however, it just not look like it is going to fly with the regulatory bodies.

 

[dicksewerrat]

I was looking at the Culvert Materials section of the PA DOT manuals for a project we were going to bid. The call out was for a 100 year design life. I didn't know CMP would last 100 years.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[civilman72]

Wow. A 100-year design life? Easy for an agency to spec, but I can see this causing potential contractors to shy away from bidding the project. And I agree that a CMP will not meet this spec, even if its lined.