PVC vs. RCP?
PVC vs. RCP?
(OP)
I'm designing a private parking lot for both cars and school buses. Trying to decide whether to use PVC or RCP. I have between 1.5' and 3' bewteen my top of pipe to the asphalt. PVC is less expensive and would save my client money but I want to make sure it will hold up to the heavier load from buses with the little cover it has. Any thoughts? Anybody ever have problems with PVC? Any problems with cracking or anything due to freezing?
THanks
THanks





RE: PVC vs. RCP?
ASTM D2321 requires one pipe diameter (or 2-feet minimum) cover over thermoplastic pipe. However, it is conjectured that this applies to soil-only cover during construction. Also the way cover is measured can vary. Typically, cover is measured from the top-of-pipe to the top-of-pavement for rigid pavements (concrete), and from the top-of-pipe to bottom-of-pavement-section for flexible pavements (asphalt).
Rigid RCP and NRCP in low cover applications may also tend to crack a flexible pavement over the centerline of the pipe. Here in the mountains of Colorado (many freeze-thaw cycles and expansive and aggressive soils) we have used both PVC and HDPE with success in low cover applications. We use 1-foot minimum from the bottom of flexible pavement section, or to the top of a rigid pavement as detailed above.
RE: PVC vs. RCP?
As for cover, I agree with ccor. The HDPE pipe needs at least two feet of cover to be safe. Where cover is an issue, you could potentially specify RCP Class IV or V for shallow depth, provided that you have 6" clear between the bell of the pipe and the underside of the pavement section (this is PA DOT spec).
Another option is to pour a 6" concrete slab over the pipe to better distribute heavy loading and protect the pipe from breaking - this goes for both HDPE and concrete.
RE: PVC vs. RCP?
RE: PVC vs. RCP?
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: PVC vs. RCP?
Plastic pipe needs good, solid, non-yielding material around it for it to have any strength.
In our county, our Road Commission no longer allows plastic for driveway culverts, not because the product is bad, but because few people take the time to install it properly.
RE: PVC vs. RCP?