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SAS Finally Moving Along


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The SAS is finally progressing towards completion.

http://secondavenuesagas.com/2010/04/22/the-mta-takes-us-inside-the-launch-box/

http://secondavenuesagas.com/2010/04/22/sas-update-the-tbm-cutterhead-arrives/

 

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“The arrival this week of the TBM at Second Avenue is a clear indicator that the MTA is delivering on a major expansion project that will have a dramatic impact on Manhattan’s East Side easing overcrowding within our transit system and serving as an economic driver for the region as a whole,” MTA Capital Construction President Dr. Michael Horodniceanu.

When fully assembled, the TBM will 450 feet long, and the cutterhead will feature 44 rotation disks designed to cut through the Manhattan Schist. In May, the TBM will make its first of two trips through the rock, and when the boring is completed, two 7700 foot-long tunnels will be ready for further work.

In its release this afternoon, the MTA offered up some vital information about the Second Ave. Subway. When Phase I is completed, it will serve at least 213,000 riders per day who currently use other subway lines, buses taxis or private cars to get around down. Transit believes it will decrease crowding on the Lexington Ave. subways by as much as 13 percent or 23,500 fewer passengers per weekday. Those who live along the far East side will see travel times reduced by up to 10 minutes. The western-most of the two SAS tubes, says the MTA, will be the first mined by the TBM.

 

-Credit to Ben Kabak

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This is awesome.

More (from MTA site):

 

Majority of Tunnel Boring Machine Parts on Site for the Final Stage of Assembly

 

The main components of the Second Avenue Subway Tunnel Boring Machine, including the 200-ton cutter head, have arrived and were lowered into the Launch Box for the final stage of assembly. Once assembled, the Tunnel Boring Machine (TBM) will begin mining the western tunnel for the new two-track line. Mining is scheduled to commence in May.

 

Click here for a complete photo gallery of the TBM being assembled in the Launch Box.

 

The Second Ave Subway TBM was originally manufactured by The Robbins Company about 30 years ago. It was first used to dig the MTA's 63rd Street Tunnel in the late 1970's and has been used on at least four other projects. The machine has been reconditioned and was rebuilt in Newark, NJ at contractor Schiavone's yard where it was assembled, tested and then disassembled for shipment to the site. The TBM was most recently used on the Fall River CSO Project in Fall River, MA.

 

The total length of the TBM plus the trailing gear which contains the mechanical and electrical equipment that powers the cutter head is 450 feet long. The cutter head has 44 rotating discs and is the vital piece of the TBM that will drill and excavate the approximately 7,700 foot-long tunnels.

 

"The arrival this week of the TBM at Second Avenue is a clear indicator that the MTA is delivering on a major expansion project that will have a dramatic impact on Manhattan's East Side easing overcrowding within our transit system and serving as an economic driver for the region as a whole," said MTA Capital Construction President Dr. Michael Horodniceanu.

 

The Launch Box, which extends from just south of 92nd Street to 96th Street along Second Avenue and is approximately 815 feet long by an average of 63 feet wide and 56 feet deep, forms the shell of the new 96th Street Station. This is also where the machine will be assembled and launched from one of two starter tunnels in May. Excavation of the Launch Box began in June 2009 using a combination of controlled blasting and mechanical methods. In total, 117,000 cubic yards of rock and soil were removed.

 

The Second Avenue Subway will reduce overcrowding and delays on the Lexington Avenue line and provide better access to mass transit for residents of the far east side of Manhattan. The line is being built in phases, with the Phase I of the Second Avenue Subway providing service from 96th Street to 63rd Street as an extension of the Q train, three new ADA-accessible stations along Second Avenue at 96th, 86th and 72nd Streets, and new entrances to the existing Lexington Av/63 Street Station at 63rd Street and Third Avenue.

 

Construction of Phase I of the Second Avenue Subway began in April 2007. When complete in December 2016, Phase I will serve 213,000 daily riders currently using other subways, buses, taxis or cars and decrease crowding on the adjacent Lexington Avenue Line by as much as 13%, or 23,500 fewer riders on an average weekday. It will also reduce travel times by up to 10 minutes or more (up to 27%) for those on the far east side or those traveling from the east side to west midtown.

 

Please visit http://www.mta.info/video to view a video of the cutter head arriving.

 

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At last! THat would've been so cool to see that being lowered into the ground.

 

I don't think they're lowered into the ground, i'm fairly sure it's assembled on-site.

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I don't think they're lowered into the ground, i'm fairly sure it's assembled on-site.

The individual pieces (cutter head, main beam, etc.) are lowered into the ground and are assembled inside the launch box chamber. Once the assembly is complete they will start the boring down to 63rd St.

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The individual pieces (cutter head, main beam, etc.) are lowered into the ground and are assembled inside the launch box chamber. Once the assembly is complete they will start the boring down to 63rd St.

 

How long does it take for it to Bore?

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I remember reading somewhere that the average rate is a block per week, and since it's boring about 30 blocks it should take a little over a year to mine both tunnels (60 weeks + approx. 10 between the two tunnel drives = 70 weeks, or a year and 3 months). That's my best guess.

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I remember reading somewhere that the average rate is a block per week, and since it's boring about 30 blocks it should take a little over a year to mine both tunnels (60 weeks + approx. 10 between the two tunnel drives = 70 weeks, or a year and 3 months). That's my best guess.

 

Man i thought it took a few hours lmfao. But why so long tho? It stops or something? Now this is so "boring".

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Man i thought it took a few hours lmfao. But why so long tho? It stops or something? Now this is so "boring".

Mining speed really depends on the rock that they are going to "bore" through. Softer rock won't be as difficult as say harder rock. Don't forget that the TBM must move through the rock, so it's not stationary. Things have to be done prudently. Also immediately after the TBM goes through a section, crews right behind it put reinforcing equipment such as the roofs and such, to prevent the newly dug tunnel from collapsing. Such equipment must arrive continuously; if not enough roof parts are delivered, the TBM cannot proceed. So it all takes time.

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Now, how many decades before trains are running? To me this means very little since sections were built before and the damn thing still was not completed.

The tunneling contract was already placed (along with the launch box contract) back in 2006 or 2007, so the funding for the tunnel is already in place. They're most likely not going to stop the TBM for duration of the project. Also, TBM's have been at work for the (7) extension and East Side Access this whole time, so the TBM for the SAS will probably finish mining all the tunnels for Phase I.

Man i thought it took a few hours lmfao. But why so long tho? It stops or something? Now this is so "boring".

The average speed is 50 feet a day, IINM. I know that's the speed the East Side Access TBM's were designed to move at, though I have heard that they average between 50-150 a day. It's because Manhattan schist is the type of rock that they are boring through, which is among the hardest rock in existence. It's not like a giant drill with the stereotypical top-shaped cutting head you think of when you think of a drill. As that cutting head rotates (slowly) it has to be pushed forward by the main beam of the machine as it rotates.

Mining speed really depends on the rock that they are going to "bore" through. Softer rock won't be as difficult as say harder rock. Don't forget that the TBM must move through the rock, so it's not stationary. Things have to be done prudently. Also immediately after the TBM goes through a section, crews right behind it put reinforcing equipment such as the roofs and such, to prevent the newly dug tunnel from collapsing. Such equipment must arrive continuously; if not enough roof parts are delivered, the TBM cannot proceed. So it all takes time.

Actually videos on Youtube show that the machine actually puts pre-cast lining on the tunnels, but you're right that they have to constantly provide that supply of materials to the TBM.

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The tunneling contract was already placed (along with the launch box contract) back in 2006 or 2007, so the funding for the tunnel is already in place. They're most likely not going to stop the TBM for duration of the project. Also, TBM's have been at work for the (7) extension and East Side Access this whole time, so the TBM for the SAS will probably finish mining all the tunnels for Phase I.

 

The average speed is 50 feet a day, IINM. I know that's the speed the East Side Access TBM's were designed to move at, though I have heard that they average between 50-150 a day. It's because Manhattan schist is the type of rock that they are boring through, which is among the hardest rock in existence. It's not like a giant drill with the stereotypical top-shaped cutting head you think of when you think of a drill. As that cutting head rotates (slowly) it has to be pushed forward by the main beam of the machine as it rotates.

 

Actually videos on Youtube show that the machine actually puts pre-cast lining on the tunnels, but you're right that they have to constantly provide that supply of materials to the TBM.

Yeah, that too. Are materials going to come by barge? I do recall though that excavated soil will be removed by trucks that would bring them to barges.

 

Yes, schist is very difficult to cut through. Much of Manhattan sits on schist, and this property allows us to develop stable skyscrapers. Now if skyscrapers sit on such rock, you would have to imagine the level of difficulty to break this.

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