Computerized Layout Generation for Sanitary Sewers

Abstract

A layout generation algorithm, called LGA, is developed for generation of sanitary sewer layouts, using a standard shortest path algorithm. For selection of the shortest path from each manhole to the final outlet, three sewer cost measures were formulated from the data on sewer lengths and surface elevations at the manholes. EX measure, which requires the definition of a hypothetical excavation volume for each sewer from the minimum cover depth and sewer slope, yielded the minimal excavations and invert depths when the generated layouts were hydraulically designed. The results were as good as, or better than, the layouts recommended for networks with up to 70 manholes. Due to computer memory restrictions, the larger networks must be subzoned for subsequent superposition. Guidelines are developed for subzoning as well as general implementation from testing of LGA with various‐sized networks.