Evaluation, Inspection, and Rehabilitation of a Major Storm Sewer in the City of Aurora, Colorado

摘要

In 2007, ICON Engineering, Inc. began a project with Aurora Water to investigate and evaluate a large diameter corrugated metal pipe (CMP) outfall system in the City of Aurora, Colorado. Initial phases of the project focused on comparing the existing hydraulic capacity with the expected discharges from the urbanized watershed and evaluating the structural integrity of the pipe. Subsequent phases included the design and construction of a relining system. In order to accomplish the project tasks and goals, a variety of methods were utilized including: dynamic SWMM analysis of the storm sewer; robotic and hands-on pipe inspection; and final design where relining was completed within the existing CMP system.The City Center outfall system was constructed in 1974 and ranges in size from 84-inches to 120-inches. The overall length of the system is approximately 4,350-feet. This pipe system serves as the outfall for a large drainage basin within a very prominent area of the City of Aurora, including the Town Center at Aurora and the Aurora Municipal Center. Given the high imperviousness of the development basin, the discharges upstream of the outfall system have the potential to exceed the system capacity. This, in combination with complicated flow splits and detention characteristics necessitated the need for a dynamic storm sewer model utilizing the EPA SWMM 5 program.Three phases of inspection, sampling, and testing were completed on the existing outfall pipe system. These phases will be discussed in detail in the final paper.This past year Aurora Water elected to pursue relining of 3,060-feet of pipeline within the existing 120-inch CMP. As expected, many obstacles were encountered in the final design phase, with the most prominent being limitations regarding pipe insertion and surface access. Construction for the relining project is anticipated to begin in December 2009.In summary, the final paper will cover the 120-inch CMP from the initial inspection to determine its present condition (extensive corrosion) through the construction of the relining in the winter of 2009/2010.