Strongest Culvert material
Strongest Culvert material
(OP)
I'm looking for the best culvert material to use in a specific application. The culvert will be running under a haul road that is basically a 2' thick aggregate road. The top of the culvert will only be covered by 18" to 24" of aggregate roadway surface at it's point of minimum cover. What would be the strongest material to use in this circumstance? I'm thinking CSP would be good? We usually use HDPE, but I don't think it would be good in this instance.
Take care,
Stoddardvilla
Take care,
Stoddardvilla





RE: Strongest Culvert material
RE: Strongest Culvert material
RE: Strongest Culvert material
RE: Strongest Culvert material
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RE: Strongest Culvert material
RE: Strongest Culvert material
Does anyone have a good reference for comparing the costs of these different pipe materials? I know HDPE is the cheapest, but how do RCP, CSP, and ductile iron compare? I'm sure ductile iron is more, but I have no idea how much more.
I used to have a sheet for estimating that called out a price per foot for different pipe materials. Unfortunately, I can't find that sheet.
Take care,
Stoddardvilla
RE: Strongest Culvert material
RE: Strongest Culvert material
I'm trying to do the calcs right now with RCP (class V). I was considering the flowable fill as mentioned above too. How exactly does one use that? I don't know how the flowable fill would fit into my calcs though, so I may just go for it without the flowable fill. I'm almost tempted to just use DIP, save some time, and call it good.
Finally, what is the strongest culvert material available? Is it DIP? I would assume strength is probably in this order (strongest to weakest):
DIP
RCP
CSP or CMP (however you call it out)
HDPE or CHDPE
VCP
Can someone correct me if I'm wrong?
Peace,
Stoddardvilla
RE: Strongest Culvert material
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IMHO, from what you descibe, this in NOT an occasion where precise engineering calcs will provide an answer - there are too many unknowns. Just use the best materials for the conditions and don't worry about it.
www.SlideRuleEra.net
RE: Strongest Culvert material
The advantage of the casing is that it will allow for some movement at the ends. That way your pipe won't deflect due to loading.
RE: Strongest Culvert material
RE: Strongest Culvert material
I noticed the quote you provided, it appears from ACPA. How about their statement also relating to their concrete pipe verbatim from their more recent ad in October 2006 Civil Engineering magazine, "Its inherent strength means it does not rely on soil support to provide the necessary structure, because it is the structure."
While I think I know basically where they are coming from and agree that all responsible engineers should carefully scrutinize the performance of particularly long-term weak, creeping types of piping (e.g. to make sure they are suitable for the level of soil support that can be practically expected in their application/area, and they will function for the Owner) that I suspect at times deal concrete some fits in the marketplace with attractive prices, "IMHO"(for whatever that's worth!) the latest ACPA ad statement is however arguably some "over the top", and perhaps even foolhardy.
While these are no doubt quite catchy words and may even sell some pipes, in my humble opinion particularly if/when you don't get good uniform support along under the haunches of any pipeline, greater loads than commonly anticipated can come to bear on some buried piping, concrete or otherwise, where it does happen to be supported by the soil mass, and these greater loads (perhaps not obvious to all practitioners in a promoted basically only two-dimensional design) might/do in some cases? compromise the load factors or longitudinal bending strengths/abilities/ductility of concrete pipes.
Thus contrary to the current claims of ACPA, I believe ALL PIPELINES REQUIRE SOME "SOIL" or other external "SUPPORT" to function properly!
RE: Strongest Culvert material
rconner:
I generally agree with your comments especially the requirement for good uniform support from bedding and at pipe haunches. This is where sand or sized granular material plays an important role. However, for a CSP for example the performance is highly dependendent on a good structural backfill compacted around the pipe at say 95 % standard Proctor and loosely compacted material above the crown for about 600 mm in the case of multiplates. In contrast the reinforced concrete pipe because of its rigidity and less deflection characteristics of the pipe material can suffice without the expensive backfill required for other pipe types excepting steel.
Anyhow, performance of pipes as well invoke other considerations apart from backfill for example undermining, erosion. In those cases a CSP pipe would fail much more dramatically than the reinforced concrete pipe since if its backfill is eroded then it collapses as a tin can.
At that stage of the game for both pipes, their functionality would be totally compromised.
RE: Strongest Culvert material
Where I work, coastal South Carolina, a high water table (usually assumed to be the surface of the ground) forces drainage pipes to be installed with very little cover, often less than the 12" specified in this post. On electric utility plant sites in this area we have used Class III and IV concrete pipe for numerous applications including aggregate haul roads used by large off-road trucks carrying coal waste products to on-site landfills. With proper bedding (but little cover), these pipes have performed for decades without problem.
In other applications, with rigid pipe, the surrounding soil is a liability rather than an asset:
Buried, pile supported pipelines going under roads. After a few years, you start to feel the "bump" as your car goes over the pipe crossing; as more time passes you can see the "bump". The buried, pile supported pipeline has remained at a constant elevation - the ground, including the road have settled. The rigid pipe is having to support the road and the traffic passing over it - yet, they can do it.
Needless to say, I am a big fan of rigid pipe, including RCP, steel, & DI
www.SlideRuleEra.net
RE: Strongest Culvert material
RE: Strongest Culvert material
RE: Strongest Culvert material
While many of us know all these different types of pipes are "apples and oranges", unfortunately to an unknowing or unwary buyer they might just be "pipe X" and "pipe Y", at $X' and $Y' material cost per foot, respectively. [Consider the case of poor homeowner who chimed in near the latter part of the parallel thread regarding also a shallow culvert application though apparently residential at http://www
Incidentally, civilperson is quite correct that Boeing 747 live loading is much larger than e.g. H20 truck loading; however, I would only like to add that it is my understanding ductile iron and I’ll bet also steel pipes have also been successfully installed under taxiways etc. (and I believe an external loading design procedure is even available from DIPRA for ductile iron pipes upon request for this application). Everyone have a good weekend!