Fluid Jackets

Abstract

To surround the circumference of plain concrete pipes with fluid jackets is a revolutionary concept that can result in maximum burial depths and live load capacities more than twice those of conventional, steel-reinforced concrete pipes. Moreover, the enhanced capacities are achievable with less than one-half the usual amount of concrete and with zero steel reinforcement. Alternatively, fluid jacketed concrete pipes may be designed with the same structural capacity as conventional reinforced concrete pipes but with a project cost savings that results from a 50% weight reduction per foot of pipe. These claims are supported by the analysis presented in this paper, which is a necessary first step before experimental validation can occur. Engineered plastic jackets encapsulate fluid (water) in a watertight configuration that encircles the buried concrete pipe. The encapsulated fluid transforms nonuniform soil pressure to uniform hydrostatic pressure around the pipe periphery. Consequently, the concrete pipe experiences hoop compression only, without the bending deformation and concrete cracking inherent in conventionally installed, reinforced concrete pipe. The fluid jacket concept has not been published in open literature. This paper illustrates the physics of the concept and presents the most promising configuration and materials determined through structural analysis studies with the CANDE-2007 computer program. Fluid jacket designs are proposed in this paper as a first step to bring this revolutionary idea to fruition. Next steps include laboratory testing, field testing, and modeling refinement.