Date of Award
Doctor of Philosophy (PhD)
Materials and Infrastructure Systems
This dissertation has involved laboratory and analytical studies of pipe head losses which were caused by: (a) smooth wye and tee fittings of 4-inch and 6-inch diameter with corresponding 4-inch and 6-inch laterals, (b) pipe liner folds created by inadequate stretching of the liner during placement, and (c) fusion joints which protrude a short distance into the pipe causing a small but unknown head loss. Though the individual loss was found to be small, cumulative losses could prove worthy of design consideration.
The velocity and head loss measurements were made using either a 4-inch or 6-inch model diameter pipe. Having made the model measurements, appropriate procedures were applied to “scale” the acquired data to larger diameters. The modeling and scaling procedures are described in detail.
The “fittings” scaling diameter dimension was limited to a trunk line diameter of 12-inches because it is the largest size for smooth pipe wyes and tees manufactured. The manufacture of these smooth fittings is described in detail.
The liner fold scaling was also limited to 12-inches because the largest available model discharge was approximately 1.4 cfs. As the model pipe was scaled upward, the head loss approached zero at the 12-inch dimension.
Useful information was gathered in the fusion joint measurements. However, it was not possible to scale the results to larger diameters because the protrusion apparently grows slightly with increasing pipe diameter. The scaling allows only the change in one dimension, which would have been the pipe diameter but not the corresponding protrusion. This problem is discussed in detail in the fusion joint portion of the thesis.
It should also be pointed out the liner fold dimensions were also held constant during scaling. This restriction was considered acceptable as it is not possible to predict the fold size in any particular pipe diameter. This scaling was restricted to 12-inch diameters also, the reason being the head loss approached zero as the diameter increased (causing a simultaneous decrease in velocity).
The acquired and computed data should be useful to the trenchless technology industry as it allows predictions of possible line losses associated with these three phenomena. A series of example calculations for a typical line length of sewer pipe are included to indicate the relative effect of various conditions in a pipe and liner.
Hart, Ellis Dale, "" (2004). Dissertation. 621.