Tough Lessons Learned and Applied: Difficult Pipe Bursting in Gresham, Oregon

摘要

Facing existing and anticipated capacity concerns, the City of Gresham needed to upsize approximately 9,000 feet of an existing sanitary sewer trunk. Among the many constraints, the City needed to make considerations for wetlands, playgrounds, buildings, and multiple creek and highway crossings. Following a creek, the existing alignment wove through commercial and high density residential properties, parking lots and public right-of-way. Modeling data suggested that the sizing requirement would be pushing the limits of pipe bursting technology at the time with upsizes of 18" concrete pipe to 24" HDPE, 12" and 15" pipe to 22", and 12" pipe to 20" with depths ranging between 8 and 30 feet. Phase 1 was designed and constructed in 2013 and provided a host of learning opportunities for the following phases. Lessons learned revolved around easement layouts; outreach and engagement with property owners, tenants and the general public; broken bursting heads; sewage diversion failure; contaminated soils and utility conflicts. Phase 2 was designed with these lessons in mind and was constructed in 2015. This paper presents a comparison between the two projects and how the lessons of Phase 1 were applied and affected the performance of Phase 2 and hopefully beyond.