Citation

Marsalek J. APWA Reporter 1986; 53(12): 32.

Copyright

(Copyright © 1986, American Public Works Association)

DOI

unavailable

PMID

unavailable

Abstract

A study is reported of head losses at several types of sewer junction manholes. The first stage of the study investigated 3 types of junctions: manholes with a 90 deg bend, junctions of a main with a lateral, and junctions of two opposed laterals. The basic manhole design without benching is characterized by large flow turbulence and concomitant high head losses. A design is described which attempts to reduce junction losses by using a semicircular benching. In another design, head losses are reduced significantly by inserting a U-shaped channel into the manhole. Proper benchings can be easily installed in new sewer systems, and junction head losses can be reduced in existing systems by retrofitting junctions with hydraulically efficient benchings made of poured concrete or other materials.