Benefits of Performance Based Large Diameter Pipeline Rehabilitation

The Miami-Dade County Water and Sewer Department (WASD) has a significant amount of large diameter wastewater prestressed concrete cylinder pipe (PCCP). WASD decided to rehabilitate some of these large diameter pipelines instead of performing pipe replacement in order to reduce operational, cost, and construction impacts. This paper discusses the benefits of pipeline rehabilitation using performance based criteria. Historically high costs, complexity of construction coordination, and traffic related impacts to the public necessitated a revised approach to addressing rehabilitation methodology. There was also a need to identify an approach that required less administration and engineering to reduce the completion schedule without increasing the existing staff. Various methods and materials construction were considered in order to address engineering and operation challenges. Resources were explored and a level of service identified by performance specification for pipe rehabilitation was developed based on flow characteristics, maximum allowable hydraulic losses, operating pressures, test pressures, and allowable reduction of inside diameter. The contractor had the final responsibility for determination of the materials, design and calculations, and permitting which was evaluated during the bid process. As a result of providing performance specifications with options for materials and construction approach, WASD has mitigated construction effects and lowered construction costs.