A new contract for the two Arrowhead tunnels on the Inland Feeder project for the Metropolitan Water District of Southern California (MWD) has been won by the JF Shea/Kenny JV, subject to a two-tier notice-to-proceed award. Shea/ Kenny submitted the lowest of two bids for the new contract in January. Its bid of $242.2 million came in below the Engineer’s estimate of $248 million and below the competing bid from Traylor Bros of $266.2 million.
Following confirmation of award in mid-April Shea/Kenny entered a limited exposure notice-to-proceed process based on approval of key submittals. Due in 90 days, these submittals will disclose the supplier of the two new TBMs required by the contract, the JV’s detailed design of the specified precast concrete bolted and gasketed segmental lining, and its intended method of handling the contract’s requirement for pre-grounting ahead of the face to control anticipated high volumes of potentially high pressure ground water inflows.
“Given the history of these tunnels, we wanted to be sure all involved agreed the way forward and that the contractor will work to the new contract specifications to get this job done,” said Dan Tempelis, MWD’s Program Manager for the Inland Feeder project. While limited exposure of $300,000, the two tier NTP process allowed MWD and the project’s construction management team Hatch Mott MacDonald to have prior notice of the contractor’s exact methods of progressing the contract and protected MWD against the liability of canceling high mobilization commitments, including TBM orders, should MWD have elected to suspend negotiations during the disclosure period. “The point is we wanted to be sure that the project will progress according to the management of risk as defined by the client’s designer rather than exposing the owner to the liability of the contractor’s appreciation and management of the perceived risk,” said Tempelis. “The process has worked well so far and we expect to grant notice-to-proceed-with-construction in late July.”
On going to press, the JV had yet to announce the TBM supplier. The segmental lining will be supplied by the Shea/Traylor/Ghazi JV casting facility in Palmdale. Jacobs Associates of San Francisco is MWD’s project designer and also redesigned the Arrowhead Tunnels.
“Work is scheduled to start on site late in 2002,” said John Townsend, project manager for the Hatch Mott MacDonald construction management team. “The TBMs are expected to start in Fall 2003. Completion is scheduled for early 2007 but is dependant on the amount of pre-excavation grouting required.” It was the inability to control heavy water inflows and at pressures of up to 30 bar that caused the first contracts for the two 5.4m o.d. x 6.4km and 9.2km tunnels to be terminated in April 2001 (see T&TNA, May 2001).
