Designing Pipes of Colossal Size with Novel Composites

Use of innovative composite systems for new pipeline construction as well as rehabilitation of existing pipes can open the door for extraordinary applications that would be too expensive or unfeasible to produce, transport, and install with conventional materials such as reinforced concrete and steel. This is more pronounced for supersize pipes over 10 ft in diameter. Once the diameter reaches above that level, production costs go up drastically mainly due to going above the typical size range of serial production with standard equipment. Another caveat is the high weight and large space these pipes take with conventional materials to an extent that it could be virtually impossible to load and transport them across the country due to roadway load restrictions in the itinerary, limited clearances under bridges, and truck bed size. As such, for super large pipes (e.g., 10 ft and above in diameter), the options are very limited. For rehabilitation, cast/cured in place systems or panels in lieu of 360-degree pipe liners are the more common options. Nevertheless, those methods have their limitations with respect to load bearing capacity, installation difficulties, as well as the need for bypassing the flow and drying out the pipe for cured-in-place components. This paper will discuss the design and production methods used to make large diameter pipes/liners utilizing a patented composite system that is comprised of glass, carbon fiber, and a proprietary core layer. Case studies including rehabilitation of a 17.5-ft sewer interceptor with a 16-ft diameter liner will be presented. At 16-ft internal diameter (ID), this is likely the largest polymeric pipe ever made as a monolithic piece.