Establishment of cover depth requirement for utility pipes in arterial roads

Abstract

Pipelines are a safe and economical mean of transporting gas, water, sewage and other fluids. They are usually buried in the ground with substantial protection. Among those utilities, water convey lines would play a vital role in supplying water to the public. At present, roads have reached their maximum capacity with the increasing of the rapid growth of traffic. Thus, the rehabilitation and widening of roads shall take place to increase the structural integrity of the road pavement and road capacity. At that moment the utility agencies have to decide whether to shift the existing lines (mainly the water lines) or keep them as they are. Therefore, a criterion is needed to decide the minimum distance above the existing lines to cater the new traffic. Furthermore, the cost of removing and replacing utility lines are generally high. Considering these facts, this research intended to identify the safe depths to locate water lines in roads subjected to different traffic loadings. Existing traffic details of some arterial roads were collected from the Road Development Authority. Heights from the existing road surface to the top of underground pipelines in some of the major roads were collected. The loading calculations were done using the „CIRCLY‟ software for a selected pavement structure. Then the bending stresses were calculated using equations. Finally, the safe depth of locating pipes for satisfying the design traffic loading was determined. Furthermore, studies can be carried out on different pavement types with different thicknesses and characteristics of pavement layers