Shani Wallis, Editor

Detroit's economic crisis has taken down another tunnel project.

On Monday (March 30), notice to terminate the contract was delivered to the Vinci/Frontier-Kemper JV on the Detroit River Outfall DRO-2 redesign and recovery project.

Vinci/Frontier-Kemper was awarded the redesigned recovery contract in October 2008. It was designed to pick up and complete the project abandoned when a deep level rock TBM tunnel being progressed by the Traylor/Jay Dee JV flooded in April 2003 to a level of impossible recovery.

That initial contract, awarded for a bid price of $93.5 million in mid-1999, was eventually terminated at the owner's convenience in January 2005. This week its $300 million successor, to progress a higher level soft-ground TBM drive to effluent risers in the river, has also been terminated.

In issuing the notice on Monday, Interim Director for the DWSD (Detroit Water and Sewerage Department), Pamela Turner, gave effective notice of 15 days in which time the JV is asked to submit an itemized statement of compensation for services performed to date. That statement will include compensation for mobilization orders, which might include and order for a Herrenknecht slurry TBM as well as possible cancellation of orders for production of the precast concrete segmental lining.

In a written statement, the DWSD said; "the Department is currently working with the Michigan Department of Environmental Quality to find mutually agreeable, and less costly, alternatives to the project approach approved for the contract with Vinci/Frontier-Kemper." It did not say when a new contract would be ready to proceed but the head media spokesperson for the Authority told TunnelTalk that it would be a new project, with a different scope of work, and a new bidding process.

Vinci/Frontier-Kemper was given notice to proceed in November 2008. The design-bid-build contract, engineered to detailed design for the DWSD by Parson Brinckerhoff, had a term of 1,826 days to a final completion date of December 31, 2013.

The original 42-month contract with Traylor-Jay Dee had a completion date of April 2003. Work had progressed positively but conditions became tough as ground water ingress around the precast concrete segmental lining in the hard rock TBM drive made backfilling the annulus more difficult and working conditions in the heading miserable. Despite various efforts to control water ingress, including installation of Bullfex-type bags to the extrados of modified rings of lining to create stop-ends in the annulus to aid backfilling, ingress overpowered the installed pumping capacity in the deep access shaft heading and flooded the 806m of 7m diameter tunnel excavated to April 2003 and its 88m deep x 10m diameter access shaft almost to the brim.

Many proposals for recovering the existing heading were considered but when the TBM and its segmentally lined tunnel was accepted as lost, DWSD engaged consulting engineer Arcadis to develop a contract redesign. One of the early successes for Traylor-Jay Dee was installation of the project's six effluent risers to deep tunnel elevation from a barge in the Detroit River. The recovery redesign by Arcadis was based on connecting a higher level soft-ground TBM tunnel to the installed risers and working from the existing access shaft, which was also a JV success.

All was set for negotiation and signing of a change order with Traylor-Jay Dee for purchase of a new machine and advance the recovery plan when the Department found it difficult politically to promote the estimated $80 million change order that nearly doubled the original contract value. The contract was instead terminated at the end of January 2005 with the intent to go back to the market place for a competitive bid for the recovery restart. It took several years and another change of designer, from Arcadis to Parsons Brinckerhoff, for detailed design of the new contract for which Vinci/Frontier Kemper was effectively the only bidder.

With only limited time since NTP in November 2008, little had been achieved on site, but this termination will cost DWSD money that it can't afford to lose and pushes out completion of the outfall by several more years. The new outfall is needed to increase capacity for effluent discharge from the Department's single large treatment plant which also managers flow from neighbouring Dearborn Heights and will also receive the extra flow conveyed by the Department's new Upper Rouge River interceptor sewer tunnel project. The existing outfall is a short, brick-lined, soft-ground facility built in the in the 1930s, that needs to come off line for structural rehabilitation and repair. The original outfall scheme was designed as a deep level tunnel to align excavation in the bedrock. This would avoid the challenges of a higher soft-ground tunnel that would require use of a complex pressurised EPB or slurry TBM, and would limit ground water problems be staying deep in rock that was predicted to be competent and present low groundwater ingress.

References

DRO-2 site visit report - TunnelTalk, Nov 2001
Upper Rouge River CSO Tunnel project CSO - TunnelTalk, Apr 2009