Masters of the Interceptors: Leveraging Trenchless Technology and Corrosion Modeling for Sewer Asset Management


Masters of the Interceptors: Leveraging Trenchless Technology and Corrosion Modeling for Sewer Asset Management

Authors:

Elaine Huber, PE, City of Vancouver, Vancouver, WA
Eric Schadler, PE, City of Vancouver, Vancouver, WA
Dan Buonadonna, PE, CH2M, Bellevue, WA
Kenneth Moffat, PE, CH2M, Bellevue, WA

Abstract: This paper includes a case study on the condition assessment and risk analysis for 40-miles of sewer interceptor, these are the City of Vancouver’s largest pipes, representing 5% of their collection system. The project included use of an advanced hydrogen-sulfide corrosion modeling to predict remaining useful life and calculate where corrosion protection or trenchless rehabilitation was more cost-effective to extend the asset's service life. A proactive asset management strategy for large diameter sanitary sewer interceptors requires 3 key tactics: a risk- based prioritization method, a means to address the known corrosion mode-of-failure, and a diverse toolbox of trenchless rehabilitation technologies. To maintain a high level of service, manage risks, and minimize costs, the City of Vancouver has developed an asset management plan that incorporates these tactics for their network of over 40 miles of large diameter sewer interceptor. In the plan, the City has adopted a conventional risk model and uses remaining useful life as the metrics for likelihood of failure, and triple-bottom-line cost as the metric for consequence of failure. The City's plan also leveraged over 20 years of historical information in the form of CCTV inspections, odalog measurements, chemical dosing records, and archived work orders in order to retroactively identify trends in performance and condition, and build a set of customized solutions for their wastewater pipelines. "Mastering" the value of this data involved a series of automated calculations, GIS scripts, and an advanced sewer corrosion model to reveal the valuable indicators for the likelihood of failure, and important factors for the consequence of failure. Lastly, when identifying potential rehabilitation options, the City compared the varying benefits of different trenchless technologies to optimize the preliminary improvement plan. This paper will review the evolution of the City of Vancouver's asset management plan for large diameter interceptors with an emphasis on the use of existing data to create optimize their approach.

Publication Date: 2018

Presented at:
NASTT’s 2018 No-Dig Show Palm Springs, California
March 25-29, 2018 | Paper Number: MM-T1-01


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