Construction will continue on the 2.5km long tunnel under Lefortovo park on Moscow’s third expressway ring road, but now almost certainly as a single tube instead of the planned twin-tube configuration. Criticism of the original design by the City Mayor’s construction adviser Mikhail Rudiak as too expensive at $2bn and unable to meet the two-year construction schedule, now looks likely to result in the second tube being replaced by a viaduct, which will be let as a separate contract. The decision is believed to have slashed costs on the tunnel by some 50% and brought the complete project costs down to $1.2bn.
Rudiak claims that the twin-tube tunnel, that would accommodate three lanes per tube, would take too long to construct using the one $200M Herrenknecht 14.2m diameter TBM bought by the City. Rudiak suggested cut and cover at $500-$600M or an elevated road across the park as alternatives. Weighing the shallow tunnel’s negative effect on the environment, the Mayor of Moscow Yuri Luzhkov has opted for three lanes of traffic through the single tube tunnel in one direction and three lanes over a viaduct in the other.
Russian contractor Organizator started work on the first tube last winter and company chief executive Arkadi Muravin admitted the contractor had already spent some $200M in addition to the machine price.
Further cost reductions of the single tunnel option could be the rescheduled depreciation of the TBM tunnelling system cost through lease payments from the contractor to the client.
Originally the full cost was to be ammortised over the Lefortovo twin tubes. It has now been suggested that the same machine could excavate two additional highway tunnels already planned for Moscow with the costs spread over the different contracts.
The proposed viaduct will be subject to a separate tender and although costs and timings are as yet unclear, the Mayor has set a stringent limit of $1.2bn for the whole Lefortovo section with completion scheduled for two years.
