Old concrete culvert load capacity 1

[NDcivil]

Hello,

First post to the forums. I'll start with a picture of what I'm talking about:

http://i.imgur.com/EutUj.jpg

Basically this is an old concrete culvert with little cover. We need the road to handle delivery trucks with wind turbine parts (max axle loads = 28,000 lbs).

The turbine supplier is concerned about the integrity of the culvert and is looking for ways to mitigate risk of bringing loaded trucks over it.

We have considered quite a few options to increasing cover, bridging with steel plates supported a few feet from the culvert centerline, or completely tearing it out and replacing it.

Does anyone know of any resources to help with analyzing a structure with this shape? (Impossible to get accurate results without knowing what strength concrete it is or what kind of rebar exists, but would be interesting to learn.)

Any insight would be greatly appreciated.

Thanks!

 

[fattdad]

it looks like a standard-issue reinforced concrete pipe. I guess you could core the concrete where exposed and try to measure strength, but the sample size would be pretty weird. You could also use the "Swiss hammer" to indirectly "measure" the strength. My bet is it's 4,000 psi concrete. It would be nice to know the pipe class as that will typify the reinforcing.

It needs more cover. It could be easily replaced to known pipe class.

I think you'd be able to reuse this pipe though.

f-d

¡papá gordo ain’t no madre flaca!

 

[cvg]

2 feet of cover over RCP is typically able to support truck loads

 

[oldestguy]

A common technique when placing corrugated pipe is to strut it,with a plank in the invert and one at the crown, with vertical struts wedged between. That would do the job if you can gain access.

However, if diam is too small to get in there and do that, I'd plank on both sides, parallel to the axis and then plank for the wheel tracks to keep as uniform a loading on the upper half, rather than a line load on the crown. Places the thing in compression, like an arch, rather than bending at the crown.

If it fails, I'd guess replacement would be less costly than a lot of work to save it.

 

[Ron]

The OP does not state if the road is existing or yet to be built. If yet to be built, not a big deal....fill and taper. If built, then steel plates work just fine but don't create a void over the pipe below the plates.

Agree with oldestguy...that will work as well.

Pipe looks competent. If you analyze, it is likely at least 4000 psi concrete. You can also excavate and encase the sides in concrete. This will prevent lateral deflection from the vertical load.

 

[Dozerman56]

I'm with cvg. Bring in enough road base/well graded gravel to put 2' cover over it and you're most likely fine.

 

[NDcivil]

Thanks for all of the replies everyone!

Ron, the road is existing. The photo in the OP is exactly what I'm talking about. Also, if we use steel plates I was planning on placing 2x6s about 4 feet from the pipe centerline to support the plates. This would give a void space for the steel to deflect into.