plastic pipe
plastic pipe
(OP)
Our client wants to use plastic pipe instead of RCP. The groundwater is within 2' of surface. I am worried about buoyancy forces lifting the pipe up. Does anyone know a quick formula to use to see if it will work or how much cover we need. Thanks





RE: plastic pipe
draw your free-body diagram and add up the vectors
downward
weight of pipe
weight of soil over the top
upward
bouyant force
use a safety factor and make sure the resultant is pointing downward
RE: plastic pipe
safety factor of 1.5 good enough?
RE: plastic pipe
check out technical note 2.107 at the following site:
http://www.ads-pipe.com/us/en/technical/technotes/index.shtml
RE: plastic pipe
Don't forget about structures, inlets, catch basins and end sections that will act to secure the pipe. I work in an area with very shallow water tables (Florida) and there is seldom a problem if the structures are not too far apart. Just be careful during construction.
Laura P, P.E.