Competitive Tendering of Alternative Sewer Rehabilitation Technologies for Large Diameter and Non-Circular Applications

摘要

In recent years there has been increased pressure for utilization of sewer rehabilitation technologies beyond traditional Cured-In-Place-Pipe (CIPP) and Glass Reinforced Polymer (GRP) segmental lining for large diameter and non-circular applications. This has included technologies such as Centrifugally Cast Concrete Pipe (CCCP), spiral wound PVC strip lining, bonded FRP liners and others. Radically different levels of product maturity, varying design approaches and quality assurance requirements often make direct comparison between many technologies complex. This paper reviews issues associated with alternative rehabilitation technologies and presents an approach previously utilized by the authors to tender large diameter and non-circular sewer rehabilitation projects with multiple sewer rehabilitation methods in a competitive yet equitable manner.Traditional CIPP and GRP lining technologies have mature and widely accepted design and Quality Assurance (QA) procedures (ASTM F1216, WRc IGN No. 4-34) in addition to a long term proven performance record. The industry standards governing CIPP and GRP liner installations create a relatively straightforward tendering process for procurement and direct comparison of cost. Alternative rehabilitation methods, including: CCCP and spiral wound PVC strip liners have some successful performance history; however, there are less proscriptive and universally accepted design, installation, and QA standards for the technologies. Thus, conventional tendering requires more detailed and relatively proscriptive specifications to ensure that design intent is achieved in the construction phase and for meaningful direct comparison of bid costs.This paper reviews steps the authors have taken to tender alternative rehabilitation methods in a competitive, equitable manner as illustrated through a case study. The case study reviews a project in Winnipeg, Manitoba, Canada, involving the rehabilitation of two large non-circular sewers; 1800x1350 (72”x54”) and 2700x1800 (108”x72”) eggs in various states of deterioration.