C303 pipe and CLSM

[Daamz]

For a 48" C303 pipe (bar-wrapped concrete pipe) rated for 10' of cover, is it usually acceptable to use CLSM (up to 1' above the pipe) if the depth of cover is around 15'-20'?

Thank you,

 

[cvg]

the CLSM will allow backfilling around under/around the haunches without compaction or entering the trench and is a good idea. make sure you dont float the pipe

 

[Pinwards]

It *might* work, but you are probably voiding any warranty/guarantee from the manufacturer by installing deeper than the manufacturer's allowed cover, so it would all be on the EOR if something goes wrong down the road.

#

 

[cvg]

my thought is that you would use the CLSM, regardless. But you will still need to design the pipe for the backfill and loading conditions. Not sure why you would spec pipe that cannot handle the loading conditions.

 

[bimr]

CLSM is not recommended for bedding material:

"The bedding material under the pipe should include at least a 2- inch layer of loose sand or unconsolidated material that can provide a yielding foundation for better external load distribution."

http://acppa.org/wp-content/uploads...e-Bar-Wrapped-Concrete-Cylinder-ASCE-2013.pdf

 

[cvg]

related question - what is the typical allowable joint deflection for 48" C303? I am not looking at deflecting for a curved alignment, but for potential uplift condition due to hydrostatic pressure