The backbone of the Washington DC Clean Rivers Project includes the construction and operation of 7 m finished diameter tunnels. The tunnel alignments total almost 25 route km, and traverse underneath existing sewage and water pipes that are paramount for the residents, federal government offices, and businesses in Washington, DC. These existing pipelines have to serve the rate payers for many decades; therefore, serviceability of these existing pipelines cannot be impacted adversely by the construction and operation of the tunnels. The authors undertook a detailed investigation of anticipated impacts on several pipelines by two of the tunnels. This paper presents the data and methodology used, and the results obtained. Based on the outcome of these analyses, the ground movement monitoring plan was designed and implemented. A summary of how the design-build bidding process benefited from the above risk management-based impact analyses is also presented.
Tunnel Impact Analyses for Washington DC Clean Rivers Project: Design Build Bidding to Protect Critical Pipelines
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