Thursday, July 8, 2010

TBM Probe Breaks Ground on 2nd Ave

-- Updates (3) can be found below

A drill that was connected to the Second Avenue subway TBM went off course at about 3 a.m. this morning and broke through the surface of 2nd Avenue at East 90th Street.

No injuries were reported and luckily the drill did not pierce the 30-inch gas main, the 36-inch water main or any of Con Edison's cables below the surface of Second Avenue in this area. If the drill had pierced a gas main, the consequences clearly could have been tremendous.

During the TBM mining operation, which is taking place about 60 feet below street level, the sandhogs perform a process known as "probing" using a rock drill to determine ground conditions and water inflows ahead of the TBM. Apparently one of the probes that they drilled went in an unintended direction and ended up bursting out into the open air at East 90th Street.

The divot in the road surface that was produced by the 2-inch drill was patched up before the start of the morning rush hour.

The first public report of this incident was made by John Del Signore on the the Gothamist blog and was based on an anonymous tip (shown below) that was posted on their website :

"Construction Accident Units Operating With A Subway Boring Machine That Accidentally Bored Through 2nd Avenue And Collapsed A Verizon MANHOLE. All Utilities Requested To Respond And Check For Further DAMAGE. Road Closures In EFFECT. Manhattan, NY 7/8/2010 4:38 a.m" reporter Gabriela Resto-Montero was on the scene this morning and shot this picture as part of her report, "Second Avenue Subway Construction Drill Pops Up on East 90th Street."

Courtesy of Gabriela Resto-Montero/

The hardhats being worn by the two men on the left would suggest that they are sandhogs. The man on the right, with the white hardhat, probably works for Parsons Brinckerhoff, the consulting firm responsible for the construction management aspect of the project.

I took these two pictures of the incident location at about 6:30 p.m. this evening with my cell phone camera.

East 90th Street & 2nd Avenue - NW corner - looking East

The location where I believe that the drill popped through the road surface is shown with the blue arrow - at a location that is about 6 feet west of the center line of Second Avenue.

The actual hole that was produced by the drill is no longer visible because it has been filled in and covered with an asphalt road patching material.

I concluded that this was the location of the drill hole because it's the only road patch in this intersection that looks like it has been freshly applied.

East 90th Street & 2nd Avenue - looking SE

This is a closer view of the asphalt patch that was applied over the hole.

Other news sources have reported that the MTA has placed the drilling of probes (for the TBM) on hold until they can determine why this morning's probe went so far off course.

This most likely means that the tunneling must also now be placed on hold since they can't safely move the TBM forward without first probing the rock ahead of the machine.

An Update - 7/9/10:
A spokesperson in the MTA's press office told me late this afternoon that the contractors at the site have a enough probe information so that the TBM can continue to mine the new tunnel while the investigation is taking place.

The diagram below shows the location of the 36-inch water main (shown in Blue) and a 30-inch gas main (shown in Green) that run under Second Avenue between 92nd and 95th streets. These mains almost certainly extend south along the avenue and pass through the intersection of East 90th Street and Second Avenue.

Source: Presentation to the CB8 Second Avenue Subway Task Force - 1/26/10 - p.5

If you assume that the location of these two mains at 90th Street are in the same location, then one could estimate that drill came up just to to the right of the 36-inch water main.

An Update - 7/13/10:

East 90th Street - looking N

I had another look at the intersection on Second Avenue and East 90th Street on my way home this evening. The spray painted notations here apparently confirm that a 30-inch gas main is present underneath this intersection.

An Update - 7/16/10:

The MTA told me this afternoon that the investigation of this incident is now complete and that the tunneling contractor has resumed probe drilling, as of today.

As an outcome of the investigation the contractor will now limited the length of probe drilling in front of the TBM cutterhead to a maximum of 80 feet. This limit will vary depending upon the elevation of the cutterhead drill point vs. the lowest elevation of utilities in the area.

I was also told that the high-speed horizontal conveyor, that transfers tunnel muck from the dump station to the muck bin, had a mechanical failure on July 9. (This explains why no tunnel muck has been carted away from the site this week.) All of the mined material is currently being stored in the muck bin (down in the launch box) until the horizontal conveyor repairs are complete.

: : : : :

In other developments...

When I passed by the launch box work site this morning I found the workers preparing to lower a set of muck cars down into the launch box, so I stopped to take a few pictures.

The muck cars are used to transport the mined rock, or muck, from the TBM working location back to the launch box work site between 92nd and 95th streets.

East 92nd Street - looking SE

: : : : :

Here's a listing of the recent additions
to the right-hand column of The Launch Box:

"Second Avenue Subway Construction Drill Pops Up on East 90th Street"
By Gabriela Resto-Montero - 7/8/10

"Subway Drill Pierces Second Avenue; MTA Investigates" (0:51)
NY1 - 7/8/10

NYC Water Tunnel No. 3
By Chris Corbett
Via Flickr
This incredible collection of more than 1,000 images documents the work of the sandhogs who are building New York City Water Tunnel No. 3. If you want to get an idea of what it probably looks like down in the new Second Avenue subway tunnel then have a look at these images.

Sunday, July 4, 2010

An Update

72nd Street - looking NW

This odd looking structure is part of the steel form that is being used to cast a concrete lining for the 72nd Street work shaft. This shaft, and the other one that's just like it [at 69th Street], will be used during the construction of the 72nd Street station.

When the construction of the new station is finished both shafts will be sealed up.

just south of 72nd Street - looking N

Another view of the work site at this location. Note the yellow rectangular crane cage on the left-hand side of the image. This cage is used to lower workers down into the hole.

This is a closeup view of the steel form.

72nd Street - looking N

82nd Streets - looking N

Utility line relocation work continues. Workers here are preparing to install either a new water main or a new gas main.

This is brand new electrically operated shutoff valve that will soon be installed.

This is close-up view of a saw that is used for cutting through the surface of the road or the sidewalk.

just south of 86th Street - looking E

A view, from the other side of Second Avenue, of Schaller & Weber.

This image shows four new sections of cement ductwork [for electric cables] that have recently been installed.

86th Street - SW corner - looking N

This now vacant location is the future home of the Ancillary Building No. 2 for the 86th Street station. The Chase branch that was at this location recently moved across the street, to the SW corner of 86th Street and 2nd Avenue.

91st Street - looking N

This Swedish made fan unit was delivered about a week ago. It will be used as part of the underground ventilation system while the tunnels are under construction. Before long it will be lowered down into the launch box by the crane that is partially shown in this image.

btw. 91st and 92nd streets

A collection of steel cables.

Just south of 97th Street - looking W

This is an the lot where Ancillary Building No. 2 for the 96th Street station will eventually be built. Workers at the moment are using a technique known as soil grouting to improve the ground in around this work area.

If you look closely at this image you can see a set of wooden braces that have been erected to provide additional support to the rear of the building on the left, which is 1873 Second Avenue.

Another view of the same lot. The pipes shown here are used during the soil grouting process.

near 93rd and 2nd - looking SW

Here's a recent view of the vertical elevator structure.

Over the past few weeks the structure has been covered with a combination of plywood and heavy green fabric. The plywood and fabric helps to keep down the dust that may be produced when the vertical elevator is in operation - and I suppose that it also makes the structure, which sits in a residential neighborhood, look a little more attractive.

East 93rd - looking SW


The same view, about 4 weeks ago.


6/29/10 - about 8.30 a.m.
Courtesy of JSL

In this image the crane on the right is about to lower the smaller crane on the left down into the launch box through the glory hole at 92nd Street.

Courtesy of JSL

Down it goes.


In other news . . .

The MTA recently issued an Invitation For Bid (IFB) Notice for Contract 3 of Phase I of the Second Avenue subway project.

This contract, which is known within the MTA as Solicitation Number C-26006, is for the complete rehabilitation of the existing 63rd Street station. This contract also includes the construction of new station entrances on 3rd Avenue.

The current bid opening date for this contract is 8/17/10.


The Second Avenue Business Association (SABA) in conjunction with CIVITAS has launched a new blog and Facebook page called the Second Avenue Shopper - and The Second Avenue Shopper on Facebook.

The purpose of the new blog is to: inform the public of events of interest taking place along 2nd Avenue on the Upper East Side, update daily specials from local 2nd Avenue merchants from 63rd to 97th streets who are impacted by the subway construction, attract foot traffic to 2nd Avenue stores, and enhance the Shop 2nd Avenue brand.


Here's a listing of the recent additions
to the right-hand column of The Launch Box

"Second Avenue businesses not digging subway"
By Adrianne Pasquarelli
Crain's New York Business - 6/20/10

"Strangled on Second Ave."
By Heather Mac Donald
NY Post - 6/21/10

Stores suffer while 2 Ave. residents earn a break
2nd. Ave. Sagas - 6/22/10

"Slow Start for Tunnel Boring Machine"
By Dan Rivoli
Our Town - 6/29/10

"Under Second Avenue"
By Diane Greer
New York Construction - 7/1/10

Determination and Findings - Second Avenue Subway
MTA Staff Summary for the MTA Board of Directors Meeting - June 2010
- Acquisition of a Fee Interest and Permanent and Temporary Easements and Terminations of Rights for Sidewalk Encroachments in Properties.
Contracts 3, 4 and 5 of Phase 1 of the Second Avenue Subway Project.

Underground Construction Regulations
Standard 1926.800
U.S.Department of Labor
Occupational Safety & Health Administration (OSHA)

Under Notices & Posters:


btw. 90th and 91st streets
as of Thursday, July 1st