Corrugated canal linings

[nlomb269]

This is Nick again from Vietnam.


We have a canal that we are trying to upgrade, and the city

authorities are sold on canal linings consisting of corrugated

pre-cast concrete sheet pilings. The surface profile of the

sections look like this:
__ __
_/ \__/ \_

The projections are 0.48m in height.

These linings will form vertical walls. The channel bottom is

unlined.

I am concerned about raising the water surface /reducing

velocities any more than necessary.

My question is - how to compute Mannings 'n' for this type of

vertical surface. I looked at k, the height roughness factor,

and also Chezy's roughness factor, and thought of computing a

composite n. My aim is to compare this surface with a

conventional smooth concrete surface. I'm not sure how to go

about this. Is there some standard method developed for such

surfaces?


I also thought of modeling with HEC Ras, with alternate cross

sections representing the projected and indented surfaces, and

using expansion/contraction coefficients. Is this a feasible

approach?

Nick Lombardi

[Sarah Craig]

Nick,
You may wish to try and contact Orange County in California. About 3 years ago they made improvements to Talbert Channel that involved removing a trapezoidal channel, and replacing it with a rectangular channel having earth bottom and steel sheet pile vertical walls. The project purpose was to increase flood conveyance. -Sarah

Phillip Jones, Senior Civil Engineer, Flood Control Design
Orange County, California
jonesp@pfrd.co.orange.ca.us
300 N. Flower St. #615, santa Ana, CA 92703
FAX 834-4572
Main Phone 834-2300


See also completed project information at:
http://www.ocflood.com/neighborhood_..._completed.asp

[nlomb269]

Thanks Sarah, I'll give it a shot

Nick