Cross culvert options

[ACtrafficengr]

I'm working on a replacement of a small box culvert.

There are driveways right next to it, so I'd like to extend the headwalls out of the clear zone rather than have holes in the guiderail where vehicles could end up in the creek. Relocating the driveways is not an option.

Because of the length, I'm looking for less expensive alternatives to precast box. We've had poor results (corrosion) with CMP. We won't have enough cover for a steel reinforced SICPP product like Contech Duromaxx.

I'm looking at RCP, but I'd need a 7 or 8 ft diameter and my state's DOT does not report bid prices for RCP over 4 ft.
[ul]
[li] Is there a reason they don't use larger RCPs? Do boxes become cost competitive at those sizes?[/li]
[li] What would be a ballpark installed cost for RCP in that size range? [/li]
[/ul]

Thanks in advance for any good advice!

 

[civilman72]

I'm guessing the reason you DOT does not have unit pricing for RCPs that large is that they have not installed any of that size. Not sure that's a reason to believe they do not allow them.

CDOT (Colorado) has unit prices for pipes close to the size you're looking for (6'-7'), see attached. They do not show these costs in 2012 or 2013, again because they did not install any during that year. These costs are for 2010 and 2011.

When you get to this size I beleive a cast-in-place box culvert would be your least expensive option, but that would probably require that the road is closed, or a phasing of the construction to allow one-way traffic.

 

[civilman72]

2010 costs attached...

 

[Twinkie]

RCP at that large a diameter is most likely cast-in-place, and job specific. That is probably why you aren't seeing any prices for it. That isn't a size I'd imagine is just sitting in the yard at the local pre-cast.

I have to imagine that a pre-cast box or arch is going to be more cost effective for you.

 

[ACtrafficengr]

Civilman, thanks for the prices. That's about half what NYSDOT pays for a similar capacity box. It's also a half continent away. It could be something as simple as precasters near here aren't equipped to make that size

We'll be closing the road. There is a reasonable detour, and it's faster, easier and usually cheaper that way.

Twinkie, I've found a number of websites that list sizes that large.

What about a performance spec? What if we specify the design storm, allowable headwater, exit velocity, etc., and see what contractors come up with?

 

[Steeleguy]

Have you considered polymer coated CSP?