Replacing Live Pipelines—Planning for Construction Issues and Sequencing Can Keep Your System Up and Running

King County and the City of Bellevue (WA) each routinely deal with construction of new and replacement sewers in their respective systems. The "Bellevue Influent Trunk and West CBD Trunk Sewer Replacement Project" represents a collaboration of the two agencies to replace existing trunk lines that serve Bellevue's Central Business District and pass through a high-density residential neighborhood. The pipelines were badly deteriorated and were reaching their capacity, with the potential for overflows to a nearby creek. This project was undertaken to meet current and future capacity needs, improve reliability, and minimize environmental impacts during construction and operation. The project replaces an existing 24-inch County trunk sewer with a new 42" line connecting to a newly upgraded 13-mgd pump station. The new trunk sewers are approximately each 2,200 feet in total length. As part of the detailed design effort, the project team carefully considered how the contractor might construct the project to prove construction feasibility, minimize property access restrictions, and to help estimate construction schedule and constructability issues. This paper will focus on how consideration of construction issues, sequencing, bypassing and sharing concepts with the contractor saved a month of time on the construction schedule, maintained property access, and reduced exposure for spillage, claims, environmental damage and negative community perceptions.