Question

A 600’ long sewer pipe is being placed into a trench. Place the pipe at a gravity drainage slope of 2% towards station 6+00. The invert elevation at its beginning station (0+00) is 5395.00’. The pipe has an outside diameter of 1’ and a wall thickness of 1”.

a) Prepare an Excel table that lists the elevations for the top of the pipe for the stations 0+00, 1+00, 2+00, 3+00, 4+00, 5+00 and 6+00 *.

b) Calculate the invert elevation for the pipe at station 6+00. *

Note: Elevations for the top of the pipe are used to place leveling rods at those stations and control the depth of the pipe during construction (since the bottom of the pipe is then inaccessible).

Answer 1

Station	Invert Elevation (ft)	Inner Diameter (ft)	Thickness of pipe wall (ft)	Longitudinal slope (%)	Top Elevation (ft)
0+00	5395	0.833	0.0833	2	5395.917
1+00				2	5393.917
2+00				2	5391.917
3+00				2	5389.917
4+00				2	5387.917
5+00				2	5385.917
6+00				2	5383.917