Using Trenchless Construction and Upfront Planning to Minimize Public ImpactsDuring Rehabilitation of a 16-inch PVC Recycled Water Transmission Main

摘要

Within 12 years after it was installed, a 16-inch PVC recycled water transmissionrnpipeline failed in seven locations near the intersection of Kanan Road and HawthornernDrive, in the Oak Park area of Ventura County. After an investigation determined thatrnthe breaks were most likely due to defective PVC material, a strategy forrnrehabilitating the pipeline was needed that met hydraulic requirements and minimizedrnimpacts on traffic and the surrounding community. As such, a variety of trenchlessrnmethods were evaluated, and pipe splitting with 18-inch HDPE pipe, supplementedrnby open-trench construction, was ultimately selected.rnThe two main goals of the project were to minimize lane closures and detours alongrnKanan Road, a busy four lane street, and limit service outages to any customer to nornmore than one week. This paper describes how these challenges were addressedrnduring the design phase through a combination of careful selection of pit locationsrnand pipe laydown areas, a detailed construction scheduling plan, temporaryrnconnections to potable water sources, and phased traffic control plans. The resultingrndesign allowed the rehabilitation to proceed with no planned closures along KananrnRoad and less than one week service interruptions. Other design considerationsrnincluded locating trenchless access pits at appurtenances to be reconnected tornminimize excavations and restraining the new HDPE pipe at connections to thernexisting PVC pipeline to address thermal contraction and Poisson’s Effect in thernflexible HDPE pipe.