Manhattan ESA drives go

22 October 2007

A 6.7m diameter Robbins TBM is due this month to start excavating the first of its two rock drives, totalling 3.85km for the East Side Access (ESA) rail tunnel project in New York. The JV contractor is Spain’s Dragados, and and local firm Judlau.

Assembly of the variable diameter main beam TBM was completed in an underground chamber below 63rd St and 2nd Ave in Manhattan, the machine having been partly built over at Queens shaft before transport under East River via the existing 63rd St tunnel to the chamber. The five piece cutterhead was designed for bolt assembly.

The TBM will bore the Westbound Manhattan Approach Tunnel for the ESA scheme, which is being developed by client Metropolitan Transportation Authority (MTA). The geology consists of schist with gneiss of UCS 80MPa-200MPa. Tunnel support is to be cast in-situ concrete in the worst areas and combinations of steels ribs, rockbolts and mesh elsewhere.

Though passing through two fault zones, in general the machine is expected to experience limited groundwater infiltration. Robbins has also supplied continuous conveyors for spoil removal.

ESA will link Long Island Rail Road (LIRR) in Queens to a new terminal at Grand Central Station, in Manhattan. The scheme involves construction of bored tunnels at either side of the existing 63rd St tunnel below the East River - the “Manhattan” and “Queens” tunnels.

Two TBMs are to drive the twin ‘Manhattan’ tunnels, the Robbins machine and a Seli supplied shield of 6.7m diameter for the Eastbound Approach. The cutterhead sections of Seli’s TBM, originally a Robbins-built shield, arrived onsite in June (T&TI, July, p11). Seli is also supplying back-up to the TBM.

The TBMs will excavate a total of four tunnels, each machine starting with a straight run before being withdrawn to restart partway along their respective tunnels to drive lower branch tunnels. The result will be 7.7km of rock bore – two x 2.15km long tunnels and two x 1.7km long tubes, stacked in pairs as they approach their respective crossover caverns and then proceed on to Grand Central Station (T&TNA, September 2006, p8). The tubes are to be completed within about 18 months.

A feature of the Robbins TBM is hydraulically-positioned supports for the front, side and roof of the machine, which should enable it to be retracted as a unit along the built tunnel for relaunch. The diameter of the TBM can be reduced to 6.1m.

The JV contractor bid US$428M to build the “Manhattan” tunnels. MTA has started the tender process for the “Queens” tunnels, which call for two pressurised face TBMs to bore four 6m i.d. tubes of 3.2km in total length. Contract award will be early 2008, and the estimated cost is US$100M. The ESA link is to be opened in 2013.


Robbins’ TBM is set to start boring on the ESA project in New York Ready to go on the ESA project Robbins’ TBM is set to start boring on the ESA project in New York ESA's Robbins machine will commence tunnelling soon

ESA's Robbins machine will commence tunnelling soon ESA's Robbins machine will commence tunnelling soon
Ready to go on the ESA project Ready to go on the ESA project