Minimum Cover over RC Pipe

[SergeL]

Can anyone provide any guidance in determining minimum cover over a highway cross culvert in the 750mm to 1050mm (30in to 42in) size range for RC pipe? The general practice in this area has been to try and place the top of the pipe below the frost line which is about 1.5m (5ft) below grade to avoid any potential frost heaving. As you can imagine this can be very restrictive in shallow draining areas. Is this approach too conservative when compared to the suggested 0.3m (1ft) minimums for live/dead loads?

 

[dicksewerrat]

you can get by with 3 feet of cover if you go to ClassV or D-Wall pipe. talk to someone at Hanson Pipe.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[LCruiser]

I've put a lot of Hydroconduit RCP (as well as HDPE and CMP) 1 foot clear of subgrade. It works fine - like everything else though, it depends on backfill.

 

[eric1037]

A good reference is "Concrete Pipe Handbook" by the American concrete Pipe Association. It has a very good section on calculating loading on pipes.

Also, check out Contech.

http://www.contech-cpi.com/

They have tables that have minimum cover for various pipe sizes.

From a soils/frost heave perspective, I would think the top of the pipe would need to be below frost depth. However, the center of the pipe should be below frost depth.

 

[Hoagie]

for non-frost areas, use min 1' cover material, otherwise spec CDF for shallower covers.