Ductile Iron pipe Vs Reinforce Concrete Pipe

[tsli001]

Hi guys,

I need some good poinst to make point for ductile iron pipe VS reinforce concrete pipe comparsion. In my case, ground cover is not an issue. I notice that DI pipe Ks is around 0.03 and RC pipe is around 0.15. So, it appear to me that DI pipe will have better hydraulic performance, but from construction point, for pipe size equal to 2400mm(around 95”). Is laying a DI pipe easier than RC pipe? Beside Ks, any other hydraulic advantage for DI pipe?

tsli001

 

[cvg]

I assume this is for a gravity storm drain?

for gravity sewers conveying surface water, ks for ductile iron concrete lined pipe is more like 0.6.

see page 5

http://www.saint-gobain-pam.co.uk/assets/docs/ws/Water_Sewer_Design_Guide.pdf

both DIP and RCP generally have centrifically spun concrete on the interior of the pipe. Other than the type of joints, I would not expect any significant hydraulic advantage for either one.

for bell and spigot pipe, gasketed joints, there is no construction advantage for one over the other.

95 inch DIP will be quite expensive and since it is generally designed for pressure application, not sure it would be worth the extra cost unless there is some structural / pressure reason to use it.

Cast in place concrete pipe might be a viable and cheaper option.

 

[fel3]

Does anyone even make ductile iron pipe (DIP) that big? The largest sizes that I have seen advertised in the U.S. is 64" (DN=1600 mm) and Wikipedia (that great fount of wisdom ) lists up to DN=2000 mm (82") in Europe.

For large diameter sewers, I would normally select reinforced concrete pipe (RCP) with a PVC liner, something like this:

http://www.rinkerpipe.com/ProdsServices/R_ConcretePipe/CP_PVCLinedPipeRein.shtml.

The largest pipe of this type I have designed is 66". BTW, that PVC liner should improve the hydraulics compared to bare concrete.

DIP for sewers also requires a special lining because neither the pipe body nor its thin cement lining will last very long in the presence of nasty gases. However, a piping expert I used to work with (he sat on several AWWA and ASTM committees) was not satisfied (as of about the year 2000) with the linings available for DIP. He said that adhesion to the pipe body was problematic. I don't know if the situation is better now or not because DIP is about my last choice for sewers so I haven't investigate this topic further. DIP is also more expensive for me here in California because there are no manufacturers west of Texas and yet I can get up to 96" RCP in several configuration (including with PVC lining) right here in town.

For low-head applications (not sewer), rubber gasket RCP without a liner works well. The largest pipe of this type I have designed is 96". For high-head applications (also not sewer), steel pipe or ductile iron pipe are probably the best choice, depending on lots of factors. I have a fair amount of experience with cement mortar lined and coated steel cylinder pipe (welded and rubber gasketed), but only up to 30".

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"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill

 

[tsli001]

Hi guys,

Thank you for you reply, I am aware of the advantage of RC pipe. Believe me the pipe is not for sewerage use. From where I came from’China’ the procurement of DI pipe is faster than RC pipe. And, we use Polyethylene lining for the DI pipe in storm drain. So that’s why ks is around 0.015. Actually, I am making a case to do the comparison to make my stand RCP is better. But, beside cheaper is there any good point for DI pipe my friends?

Tsli001

 

[cvg]

I have never used (large) DI pipe for a drain. For small drains (under 12"), DI or cast iron might be used

 

[beej67]

DI is more expensive, harder to install, and doesn't offer you any real benefit other than structural strength. I've used large DIP when I have to punch a storm drain through a retaining wall or similar.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[cvg]

i prefer modifying the retaining wall

 

[dskzeus]

I did not know what the coefficient "K" stands for. If it refers to roughness coefficient than in terms of Manning's coefficient for roughness "n" the materials are considered equal. Therefore, there is no advantage of one material over the other.If you lined the DIP it would be better hydraulically.


In my part of the country we do not use a 95 inch ductile iron pipe for storm drain systems. We would use a 96 inch. A 96 inch ductile iron pipe is not a shelf item and must be a special order.Therefore, there is a premium price if you ordered it. For this size it has normally been RCP, CMP,, OR RCB.
In terms of construction the RCP would be shorter and lighter and easier to handle.The DIP would be longer, be heavier; and perhaps, be harder to handle.
The DIP what have less joints than the RCP but you would need a bigger crane and the contractor would have to place an advanced order.
Traditionally, in my part of the country the choice would be RCP.