J.F. Shea Company, Inc.

Tunnel visions You might think that large-scale excavation and the construction of a 7,100-foot-long rail tunnel would be enough to make any town grind to a halt. However, Andrew Pelis learns, life continues apace in the city that never sleeps, as one of New York CityÔÇÖs newest features starts to take shape, thanks to J.F. Shea Company. While GothamÔÇÖs streets are alive with hustle and bustle, little does its population realize the industry currently taking place beneath its feet in the development of the Metropolitan Transportation AuthorityÔÇÖs Number 7 Line Extension Project, which is extending the 7 Line service westward from its current terminus at Times Square to a new station at 34th Street and 11th Avenue.  The $1.14 billion contract to build the tunnels and the 34th Street Station shell was awarded to a joint venture group known as S3II, which is headed up by J.F. Shea Company in partnership with Skanska and Schiavone Construction. The work to complete the station entrances and finishes, as well as support facilities such as ventilation and traction power substations, will be awarded in future contracts. The cost of the full project is expected to be in the region of $2.1 billion and is largely financed by the City, which has the ambition to re-invigorate the West Side of midtown Manhattan into a vibrant 24-hour neighborhood containing a mix of commercial, residential, retail, open space and recreational uses. ÔÇ£Our job has been to excavate and build the tunnel, and we are now in the process of building the station,ÔÇØ explains Shemek Oginski, site manager at J.F. Shea. ÔÇ£The station itself will be built in front of the busy Jacob K. Javits Convention Center, which is not currently supported by the subway system.ÔÇØ Two tunnels are currently being created that will continue south under 11th Avenue to 26th Street, and Oginski says that the length of tunnel between 34th and 25th Street will create storage areas for the trains. ÔÇ£We are using two large tunnel-boring machines [TBMs] built by the German company Herrenknecht, which place precast concrete liner segments as they dig, creating the tunnel interior. We are excavating the tunnels full-face and boring at a diameter of 22.5 feet. This method allows for the immediate installation of support for the tunnel.ÔÇØ The dimensions of the project are impressive: overall the tunnel will be 6,000 feet long, but J.F. Shea has also been involved in the creation of a 1,000-foot-long cavern, some 45 feet high and 60 feet wide, which will form the shell for the new station. Oginski and his colleagues from J.F. Shea are well versed in the importance of underpinning work and have used their extensive knowledge of working in varying environments, where the ground presents real challenges to creating a tunnel structure. ÔÇ£We are headquartered in Walnut, California, and have a rich history of building landmark structures, including the Golden Gate Bridge, the Hoover Dam and San FranciscoÔÇÖs Bay Area Rapid Transit system. In particular, some of the project work weÔÇÖve undertaken in California has presented extremely difficult ground conditions, and we have benefited from what weÔÇÖve learned there, particularly when it comes to pre-planning.ÔÇØ As with all construction projects in Manhattan, pre-planning forms a crucial part of the process, and in the case of the 7 Line Extension Project, it began to some extent even before the contract was awarded to S3II. ÔÇ£ItÔÇÖs really a challenge working downtown,ÔÇØ acknowledges Oginski. ÔÇ£There are lots of restrictions in regards to site access, getting deliveries, working in the neighborhood, and noise and vibration controls. Overall, the process took several months, and we did this when we estimated the job and negotiated the job with the owner. ÔÇ£The detailed planning then started after we got the job and has continued through each phase,ÔÇØ Oginski continues, ÔÇ£as our contract will last for four and a half years. This is a typical kind of project for us, as tunnel work is very specific and there arenÔÇÖt many companies in the United States with our capabilities.ÔÇØ All told, there are roughly 400 people working on this contract, which is focused on three main sites. The sheer size of the project offers challenges, as Oginski explains. ÔÇ£The first site is the area where the two boring machines are operating,ÔÇØ he describes, ÔÇ£while the second site is the cavern for the station at 34th Street. The third main area will be the tie-in to the existing tracks on the 7 Subway and will be located under the main Port Authority Bus Terminal. At the moment our Swedish partner, Skanska, is doing the underpinning work at this site. ÔÇ£With so many people and three key locations,ÔÇØ Oginski goes on to say, ÔÇ£it can be a challenge to coordinate things, but we work three shifts around the clock, and we have supervisorsÔÇöincluding safety officersÔÇölocated on each site for every shift. It has also been important for us to work closely with the local labor unions.ÔÇØ The use of IT has also assisted J.F. Shea in all processes and has greatly improved communication links with the owners. ÔÇ£We have been using the Constructware System,ÔÇØ Oginski says, ÔÇ£and everything has been downloaded, so we are operating with virtually no paperwork. Technology has also allowed us to keep an eye on the progress of the two TBMs, and at anytime I can check on the parameters, their location and production. This is the first time IÔÇÖve used this system, and itÔÇÖs working well here.ÔÇØ S3IIÔÇÖs work is due for completion in September 2012 and remains within budget and on schedule. ÔÇ£We still have around 2,000 feet of one tunnel to excavate, and the other one has around 2,500 feet remaining to break through,ÔÇØ states Oginski. ÔÇ£WeÔÇÖre still working on the cavern; it has been excavated but now needs to be lined with concrete, and weÔÇÖll also need to build emergency exits. Once we have finished and moved the machines out, the tie-in with the existing train line can take place, though we are not responsible for laying the final rail in place in the tunnel.ÔÇØ That last piece of the jigsaw will complete an enormous project that will make the journey to the West Side or the Javits Center that much easier for future generations.