Tuesday, September 13, 2011

Brilliant Morning Light on Second Avenue


As we turn the calendar from August to September, we know that summer is nearing an end. As the days get shorter, the shadows along Second Avenue are only getting longer. Still, the brilliant morning light enhances the many bright colors found throughout the work site.

On a recent Friday morning, I set out as early as I could bear in order to capture the ongoing construction work, and the shadows of the rising sun over the active work site.

The MTA's contractors on Second Avenue start work at 7 a.m. I arrived shortly thereafter, and this is what I saw through the lens of my camera.



9/2/11
97th Street - looking S

Workers at this location are in the process of excavating a section of slurry wall trench using the machine shown in this image. The trench will be excavated to a depth of about 100 feet.



9/2/11
btw. 96th and 97 streets - looking NE

Another view of the same machine - in which you can clearly see the hole where the trench is being excavated.

The yellow hose in the foreground is used to deliver a slurry mixture into the trench as they dig. The slurry, which is a mixture of clay and water, keeps the walls of the trench from collapsing.



9/2/11
btw. 95th & 96th streets - looking NE

Once the trench has been excavated, a 100-foot long rebar cage, like the one shown above, will be carefully lowered into the hole.



9/2/11
just south of 96th street - in front of the Rite Aid - looking NE

After that, workers will lower a long tremie pipe into the newly dug trench. Fresh concrete will be poured into the pipe so that the trench can be filled with concrete - from the bottom up. As the concrete rises, the slurry mixture is pumped out so that it can be recycled and used again.



9/2/11
on 95th Street, about 100 feet to the west of 2nd Avenue - looking E

At other locations on the job site, workers were in the process of assembling new rebar cages.

Workers in the image above are just about to start building a new cage on top of the wooden frame shown in this image.

Note the worker (with his protective helmet) who will soon start welding sections of rebar together at this location.



9/2/11
just south of 97th Street - looking NW

Workers in this image are wrapping sections of rebar using heavy steel wire. Basically they are wrapping the sections together so that they don't move when the cage is lifted and lowered into the trench.



9/2/11
btw. 95th & 96th streets - looking E

At a different location on the site, a second machine can be seen excavating another section of slurry wall trench.



9/2/11
87th Street - looking SW

At this location, workers are excavating an access shaft that will be used during the construction of the new 86th Street station. The excavation here is being performed using a technique known as controlled blasting.

Even though the blasts are controlled, they are still quite loud.



9/2/11
btw. 86th & 87th streets - looking W

Another view of the same shaft site. In the lower right corner of the image, you can see a rock drill (which was incredibly loud) boring holes into the bedrock. The explosive charges will be lowered into these holes.



9/2/11

A closer view of the rock drill. If you enlarge this image and look very closely, you can see that the workers are, of course, wearing ear protection.



9/2/11
83rd Street, just to the east of 2nd Avenue - looking W

A view of the site where the other 86th Street station access shaft is being built.



9/2/11
83rd Street - looking E

Another view of the same shaft location, from a different angle.



9/2/11
73rd Street, NE corner

On the left in this image, you can see a environmental monitoring station. At this location, the contractor appears to be monitoring both the sound level and the quality of the air.



9/2/11
79th Street, NE corner - looking SW

Workers at this location, in the middle of Second Avenue, are operating a pumping station that is being used to deliver concrete down into the west tunnel below. The concrete is being used to line the walls of the new tunnel.



9/2/11
69th Street - looking N

A view of the MTA's Muck House between 69th and 72nd street on Second Avenue.

This nondescript temporary structure houses a set of electric winches and skips that are being used to transport muck from the station cavern below to waiting dump trucks at street level.

An identical structure, which can be seen in the distance in this image, has also been put up between 72nd & 73rd streets.

The workers on top of the structure appear to be installing sound insulating material under the roof.



9/2/11

Another view of the work taking place on the roof.

Note the reflections of bright sunlight on the building and the muck house, above and below.



9/2/11

A closer view of the insulation being installed under the roof line.



9/2/11
69th Street - looking N

A view into the muck structure at this location, through the south entrance.

The workers here are lowering a [red] box of supplies(?) into the shaft.



9/2/11
70th Street - looking W

A large section of ventilation pipe is carefully walked down the street.



9/2/11
72nd Street - looking N

A view into the muck structure at this location, through the south entrance. The orange device in the foreground is a mobile ventilation fan.

Workers in this image are lowering one of the skips down into the access shaft.



9/2/11
73rd Street - looking S

A view into the muck structure at this location, through the north entrance.

If you look carefully, you can see rock and other material (i.e. muck) being dropped into the waiting dump truck. The worker on the ladder would appear to be checking to see that they don't load too much material into the truck.



9/2/11

A sign posted on an entrance to the muck house.



9/2/11
72nd Street, NE corner - looking N

A view of the deep cavern that now exists between the muck house and the residential building on the right.

One could assume that the exterior walls of the muck houses have been painted an off-white color so as to reflect as much natural light as possible into this corridor.



9/2/11
73rd Street - looking S

A view of a dump truck that has just entered the structure so that it can be loaded.



9/2/11
73rd Street

This hand-made sign announces the final performance [on Second Avenue] of Gary Russo, the now famous singing ironworker.

At last count, his original video has been viewed by over one million people on YouTube.



9/2/11
63rd Street, btw. Lexington & 3rd - looking E

At this location, on the north side of the street, workers are excavating part of the plaza so that they can access the existing station below.



9/2/11
63rd Street & 3rd Avenue, SW corner - looking S

A survey team at work, at 7:10 a.m.



9/2/11
Existing Lexington Avenue/63rd Street station
Track 1 - Southbound
Looking W

Passengers waiting for a southbound F train.

This station is in the process of being completely renovated as part of the project. The renovation includes the activation of a set of long dormant tracks on the other side of the orange wall, and the opening of four new station entrances on 3rd Avenue.


::


A Note About the Current Location
of the Tunnel Boring Machine (TBM):


As of 7 a.m. on Tuesday morning (9/13/11), the TBM was 296 linear feet away from its final destination: the lower level of the stub cavern at the Lexington Avenue/63rd Street station. This would put it somewhere near the middle of the city block that is bordered by 63rd & 64th streets and 3rd & Lexington avenues.

With good rock (i.e. rock without fractures, so they can mine 50 to 70 feet a day) they most likely will [now] break through into the stub cavern sometime early next week.

Please stand by for further news...

Update - 9/20/11
As of 7 a.m. today the TBM had just 77 feet left to mine.


:::::


Off Topic:
The Tenth Anniversary of 9/11

I know that this is off-topic, but I felt compelled to include a few links here to mark the passing of the tenth anniversary of 9/11.

The four pieces that I selected, all from The New York Times, highlight the men and women who are working to rebuild the World Trade Center site.

"The Workers"
By Fred Conrad, Nick Harbaugh and Andrea Rice
The New York Times - 9/8/11
"The World Trade Center site employs more than 3,200 workers. At present, it is the largest construction project in the United States. These portraits [146 in total] and audio narratives are a testament to their myriad skills and talents."

"Ironworkers of the Sky"
By Randy Kennedy
The New York Times - 9/4/11

"Raising High Steel Atop 1 World Trade Center"
By Damon Winter
The New York Times - 9/4/11
Eleven black-and-white photographs by the Damon Winter, a Pulitzer Prize-winning photographer for the newspaper.

"Reaching the Heights"
By Dean Robinson
The New York Times - 9/2/11
A behind-the-scenes look at how Damon Winter got his pictures from the top of 1 World Trade Center.

Friday, September 2, 2011

TBM NEARS END OF RUN


Second Avenue Tunnel Boring Machine (TBM)
Nears the End of its Second Run


Breakthrough into Existing Lexington Avenue/
63rd Street Station Just Weeks Away


Recently released data indicates that the TBM working under Second Avenue is now about 500 feet away from its final stop, the Lexington Avenue/63rd Street station.

Based on its current rate of progress, it could be estimated that it will hole through into this station on or about Friday, September 16th.

The TBM, known to the sandhogs as the worm, started its second run (the east tunnel) at a point just south of 92nd Street back in March of this year. Since then it had mined a total of 7,221 linear feet, as of August 31st.

The 485-ton, 450-foot-long machine is now in the process of making a relatively tight westerly curve as it grinds its way towards a stub cavern at the Lexington Avenue/63rd Street station. The stub cavern, shown in the diagram further along in this posting, was built in the late 1970s when this station was original constructed.

The TBM previously mined 7,162 feet of the west tunnel under Second Avenue.

Phase I of the Second Avenue subway (i.e. the extension of Q Line service to the Upper East side) is currently scheduled to be completed in December 2016.



Partial Diagram of Phase I of the Second Avenue Subway
Google Maps
(left-click on the image above for a closer look)
-- The approximate location of the TBM, as of 8/31/11,
is designated with a red cross on the map above.



G3/G4 Tunnels and 72nd Street Station
Second Avenue Subway
(left-click on the image above for a closer look)

This diagram details the current and planned subway tunnels just to the east of the Lexington Avenue/63rd Street station.

The G3 & G4 tunnels (shown above) are being built as part of Phase I of the project. The tunnels designated as S1 & S2, for the future "T Line", will be built during Phase III of the project.

::

Last Reported Location
of the Tunnel Boring Machine
btw. 64th & 65th streets
as of 8/31/11

TBM Run No. 2 (east tunnel)
Tunnel length: 7,789 linear feet (LF)
Start: just south of 92nd Street
End: Lexington Av / 63rd St Station
7,221 LF mined as of 8/31/11
568 LF to run

August TBM Mining Data:
Distance mined: 1,265 linear feet (LF)
TBM mining days: 23
Avg. distance per day: 55 LF


:::::


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

"No Subway, but a Little Silence on Second Avenue"
By Michael M. Grynbaum
The New York Times - 8/15/11

"No more underground blasts at night on 2nd Ave" (2:00)
Video
By Jeff Pegues
WABC-TV - 8/15/11

"MTA behind schedule, over budget on two mega projects, feds say"
By Marc Beja
amNew York - 8/22/11

Feds: East Side Access, SAS won’t open until 2018 - 8/22/11
By Benjamin Kabak
2nd. Ave. Sagas - 8/22/11

"Underground Economy: Cashing in on Rubble From the 2nd Avenue Subway" (4:08)
By Ilya Marritz
WNYC - 8/23/11

"A Bonus for First Avenue: It's Not Second"
By Laura Kusisto
The Wall Street Journal - 9/2/11


::


A Footnote:

After four years I've decided that its time to change the layout of this blog. The layout (known as a template) that I selected when I started in 2007 is so old its not even available on the current blogger.com web site today!

I plan to adjust the new template over the next week as I play with all of the new options. In the meantime, please stand by while I rejig the blog a bit.

Ben

Sunday, August 14, 2011

Reporting on the Reports


With this post, I am going to highlight several key reports that have been issued over the past two weeks. These reports are available on the MTA's web site, if you know where to look.

Updates: 8/15/11 & 8/23/11
The MTA has now set a 7 p.m. cutoff time for blasting associated with the new 72nd and 86th street stations. Details have been provided in the updated sections below.



Second Avenue Subway, Phase I Quarterly Report
Report Period: 2Q2011 (April, May, June 2011)
MTA Capital Construction
To find this report on the Internet, follow this path: www.mta.info >
Capital Program > Building the Future >
Second Avenue Subway > Documents

This 29-page report includes a great deal of detail on the project,
as one might expect.

Highlights include:
  • The forecast date for revenue service on the new line under Second Avenue remains December 30th, 2016.
  • The current schedule now includes 67 calendar days of schedule contingency(*). This is a significant reduction in contingency days vs. the 168 day number detailed in the 1Q2011 report. The lost days are primarily due to the five month delay awarding the 86th Street Cavern Mining contract.
  • The contractor mining the 72nd Street Station Cavern has excavated 20,255 BCY (Bank Cubic Yards) [11.9%] to date, of the 170,507 BCY total.
(*) Schedule contingency is "planned extra duration" in the schedule to allow for unexpected delays.

::



Second Avenue Subway (*)
MTA Capital Construction presentation
to the MTA Board of Directors
Capital Program Oversight Committee
July 2011
Location on the Internet: www.mta.info > About the MTA >
Board Materials > 7/25/11 - Capital Program Oversight Committee

Significant critical milestones and issues include:
  • The active lawsuit between Yorkshire Tower residents and the MTA concerning the planned entrances on 86th Street.
  • Delays on the active 96th Street Station contract related to the relocation of utilities.
  • Delay of the award of the 86th Street Cavern Mining contract, by five months, due to the need to obtain a "Buy America Waiver" from the FTA for part of the contact.
The report also includes a detailed Risk Assessment for 86th Street Station Cavern Mining contract.

Additionally, the report includes an interesting 3D view of the planned 86th Street station, shown below:




(*) Note: This 15-page report unfortunately is part of a 161 Mb PDF file on the MTA's web site. It may take some time to load if you click on the link. If the MTA had optimized the PDF file using Adobe Acrobat that could have reduced the file size to just 26 MB.

::



MTA Capital Program Milestones Report - p.38
as of 6/30/11
Location on the Internet: www.mta.info > About the MTA >
Capital Program > Resources > Capital Program Dashboard >
MTA Capital Program Milestones

The timeline consists of six months of historical events and
24 months of planned events.
2010-2014 Capital Program Milestones are tracked using colors: Green: on-time (early or within 0-3 months), Yellow: 4-6 months late, Red: 6 months late.

::



SAS - Contract C4B (72nd St. Station Cavern)
Community Air Monitoring Exceedances: 1/1/11 - 7/12/11
MTA Capital Construction

This report details air monitoring exceedances (dust and total volatile organic compounds) in and around the 72nd Street station cavern mining work zone.

The issue of dust and odors has been a concern for residents near this 72nd Street station work zone for some time. The matter was to be addressed at a special meeting of the Community Board 8 Second Avenue Subway Task Force last week. However, that meeting was cancelled after the MTA sent this letter to Community Board 8.

It is expected that air quality concerns will be discussed at the September meeting of the CB8 SAS Task Force, after the MTA has completed a review and study of the air quality due to the SAS construction activity.


::


Now on to a few other points of interest --



Long-term Construction Look Ahead Map
(Beta version)
MTA Capital Construction

MTA Capital Construction recently launched a new interactive Long-term Construction Look Ahead mapping tool on their web site.

The tool allows a user to view a map of the planned construction-related information for every block within the project corridor - from 63rd Street to 100th Street - on a quarterly basis through the middle of 2013. Information related to the later years of the project will be added in time.

To use the tool, click on the image above and then click on the word "Map" on the MTA's web page. Then click on any of the construction zone icons and a page will appear containing information on construction activities, location, duration of work and traffic restrictions.

You can move the map from left to right by moving the slider bar. You can also select a future period by clicking on one of the blue buttons. (For example, if you click on the Q3 button on the 2012 row, the site will display a map that details the planned construction-information for this period.)


::


MTA Capital Construction awarded the the 86th Street Station Cavern Mining and Heavy Civil Structure Contract, referenced as Contract C-26008, on 8/4/11 to the firm Skanska / Traylor JV. The award amount was $301,860,000, which was the low bid for this contract.


In related news, the MTA issued the following notice of Controlled Blasting for the 86th Street Station Access Shafts.


Blasting Notice - 86th Street Station Cavern Shafts
MTA

The notice says that the contractor will soon start blasting out two access shafts on the east side of Second Avenue at 83rd St Street (the South Shaft) and mid-block between 86th and 87th streets (the North Shaft).

According to the notice, blasting in the South and North Access Shafts (for 86th Street Station cavern) is permitted to take place between 6 a.m. and 12 a.m.
[These times are no longer valid - see the updates below]

Update - 8/15/11
Michael Grynbaum of The New York Times reported this morning, in his article "No Subway, but a Little Silence on Second Avenue", that the MTA has told its contractors that there should be no blasting on Second Avenue after 7 p.m., effective today.

Update - 8/23/11
The MTA just provided me with the following statement regarding the blasting on Second Avenue:

MTA BLASTING NOTICE UPDATE

"In acknowledgement of community concerns related to late night blasting activities associated with the Second Avenue Subway Project, MTA Capital Construction has revised project blasting hours to address the issue.

As of Monday, August 15th, MTA Capital Construction has instructed its contractor that all blasting is to occur prior to 7 p.m. on a regular basis.

The following exceptions will apply:

· Blasting that would affect operations at Memorial Sloan-Kettering/ 64th Street Outpatient Center will be scheduled to occur later in the day to avoid interference with patient care.

· Unforeseen circumstances, limited to instances where there are safety concerns. In those limited instances where post 7 p.m. blasting becomes necessary, an email notification will be sent out to the Community Board, local elected officials and all interested community representatives.

Blasting times in the shaft are from 7 a.m. - 7 p.m., with the two exceptions as noted above.

Blasting for excavation of the shaft at 86th Street will begin in approximately 2 weeks. Blasting for the [86th Street station] cavern will follow excavation of the shaft and we believe that will take place in approximately 2-3 months."


::


And finally a few images --

Here are two images of the work taking place deep inside the the Lexington Avenue/63rd Street station:


Source: Judlau Contracting web site

This would appear to be the out-of-service north side of the station.



Source: Judlau Contracting web site

This would appear to be a view of an unused portion at the east end of the station, under 3rd Avenue.


::



Source:
"The most powerful block in NYC that you’ve never heard of"
Untapped New York - 8/8/11

This image shows a section of the power distribution panel at the New York City Transit Power Control Center. Note the reference to the "future Second Ave. Line".

The designations G3-SB and G4-NB refer to the out-of-service tracks on the north side of the existing 63rd Street / Lexington Avenue station. These tracks will be used when Q Line service is extended to the Upper East Side under Second Avenue.

T1-SB and T2-NB refer to active F Line tracks on the south side of this station.


::


Last Reported Location
of the Tunnel Boring Machine
btw. 69th & 70th streets
as of 7/31/11

TBM Run No. 2 (east tunnel)
Tunnel length: 7,789 linear feet (LF)
Start: just south of 92nd Street
End: Lexington Av / 63rd St Station
5,956 LF mined as of 7/31/11
1,833 LF to run

July TBM Mining Data:
Distance mined: 1,468 linear feet (LF)
TBM mining days: 20
Avg. distance per day: 73.4 LF



:::::


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

"2nd Ave. Serenade"
By Danny Gold and Jennifer Fermino
The New York Post - 8/2/11
With over 800,000 views on YouTube, surely just about everyone must have heard of Gary Russo, the 2nd Avenue singing iron worker, by now.

"Second Ave. Concrete Meets Test"
By Allen Houston
Our Town - 8/10/11

Sunday, July 31, 2011

Take Me Back to 1973!


And now a trip back in time, to 1973 --

It may seem hard to imagine, but this isn't the first time that the MTA has attempted to build the Second Avenue subway. (Yes, really!)

Ground was first broken for the Second Avenue subway line back in October of 1972 at 103th Street by Governor Nelson A. Rockefeller and Mayor John V. Lindsay. Two years later, in 1974, 27 blocks were under various stages of construction: Chatham Square to Canal Street, 2nd Street to 9th Street, 99th to 105th streets, and 110th to 120th streets.

This posting documents a section of the line that was built between 110th and 120th streets in East Harlem. This portion of the line is known by the MTA as "Route 132A Section 13".

The contract for this section of the Second Avenue subway was awarded by the the City of New York and the New York City Transit Authority to Cayuga Construction and Thomas Crimmins Contracting, a joint venture, in early 1973.

The contract award amount, in 1973 dollars, was $34,450,000. (Which is about $175 million in 2011 dollars, according to the Department of Labor's CPI Inflation Calculator.)

Cayuga Construction Corporation's background was mainly in heavy public construction, including extensive New York subway work. Thomas Crimmins Contracting, which was founded in 1847, was one of the top deep foundation construction companies in New York at the time.

The Transit Authority contract called for Cayuga-Crimmins to construct the structural shell for a two track subway tunnel between 110th Street and 120th Street, using the cut-and-cover tunneling method.

Work on the contract started in April 1973 with initial efforts focused on three major tasks: (1) the relocation of underground utilities, (2) the installation of an external dewatering system to lower the water table along Second Avenue and (3) efforts to underpin the foundation of many of the adjacent buildings.



1974

In this image, the contractor is using a crane to lift a steel beam into position on the outer edge of the excavation site. This steel soldier pile is being used as part of a soil retention wall along the outer edge of the site.



1974

Another view of a soldier pile beam being positioned by a pair of workers.



1974

In this image, the soldier pile is being driven down into the soil using a pile driver. (Thankfully, pile drivers are not being used extensively by the contractors who are working on the project today. These machines are very noisy pieces of equipment!)



1974

Workers in this image are excavating trenches for the deck beams that will run across Second Avenue.



1974

Workers here are positioning 36" deep steel deck beams across the avenue. This operation was done at night so that Second Avenue could be closed to traffic.



1974

Deck beams here are being moved in to place.



1974



1974
Second Avenue - looking north

This is an aerial view of the temporary timber decking (the brown road surface) across Second Avenue. The 12-inch thick timber decking enabled the traffic to pass over the excavation site.



1974

A view under the timber decking.

The contractors were always "fighting water" on this project due to the high ground water level and significant concentrations of varved silt (which is called "bull's liver" by many New York City contractors) in the work zone.

Varved silt was deposited in the New York City area by ancient glacial lakes that once existed in the region. It is a particularly difficult substance to dewater.



1974

Another view under the deck. The small structure in this image would appear to be a water pumping station.



1974

In this image, and the one below, you can clearly see the timber lagging that is used to hold back the soil (behind the soldier pile wall) as the excavation progressed.



1974

In this image, you can see part of the dewatering eductor system that was used to remove ground water from the other side of the wall.



1974

The worker here is drilling holes in preparation for blasting out the rock.



1974

Excavation of rock and other material from the floor of the work site under Second Avenue.



1974



1974

A view of a soldier pile tip which required underpinning and bolting.



1974

Soil removal from inside the excavation.



1975

Inside the excavation. Note the two levels of support struts and the rising rock line on the left.



1975

This image shows the installation of the structural steel for the tunnels, and the supports for the roadway above.



1976

A view of the nearly complete subway structure with temporary lighting. (Note that the contract did not include the installation of track or signals.)


In 1975 the Transit Authority began a process to shutdown the entire Second Avenue subway project by not awarding any new construction contracts for the line. This was done after political leaders decided that no further funding would be made available for the project.

The Second Avenue subway tunnel in East Harlem that was built by Cayuga-Crimmins, which was finally completed in 1978, will be used when when Phase II is built . . . someday.

::

Second Avenue was a difficult construction job and a financial disaster for both Cayuga Construction and Thomas Crimmins Contracting.

In 1979, Cayuga-Crimmins ended up in a court case that they brought against New York City and the Transit Authority. Cayuga-Crimmins sought to recover damages for additional expenses allegedly incurred as a result of unanticipated subsurface conditions (i.e. underground water, soil subsidence and unanticipated rock formations) and disputed work claims.

The case dragged on for a decade until it was finally settled right before it was to go to trial. By that time, Cayuga Construction had closed down its operations (in 1984) and Thomas Crimmins Contracting had been acquired by Yonkers Contracting.


A final word about the impact that the project had on the local community along Second Avenue in East Harlem.

There was serious community impact during the course of the construction work. The section from 110th to 120th streets was entirely open cut with steel and timber decking.

Decking beams were installed at night with several blocks closed to traffic. Parking was restricted during daylight work hours which caused problems for residents and store owners.

Construction operations caused excessive noise in spite of various attempts to reduce it. As example, a dewatering system pump station which operated around the clock was built on a Jefferson Houses lawn and, in spite of large silencers, could be heard in the top floor apartments.

Over 50 buildings adjacent to the excavation had to be underpinned. All buildings were monitored for movement. In one instance a building showed some tilt and was ordered vacated by the city - a step that the contractor thought was unnecessarily because the movement had stopped.

::

Update - 8/8/11

The following comment, paraphrased below, was posted soon after the posting went live last week. I've now posted it here, along with a reply from the project engineer, for others to read.
"It's amazing how many of the construction techniques used are similar to those being used today.
One of the biggest differences I see between construction methods now and then is how they shored the excavation. In the 1970's photos, it appears that they used timber planks to shore the sides of the excavation between the soldier piles to keep the bull's liver from liquefying and "running" through the boards.
All of the new support of excavation walls (slurry and secant, in the launch box and at the 96th Street Station sites) are made of concrete so that they are impervious.
I am told that Cayuga-Crimmins' neighboring contractor, who built the 99th - 105th street tunnel section back in the 1970’s, used steel plates instead of timber to they would have impervious walls.

I wonder if Cayuga-Crimmins had issues with the bull’s liver running into the excavation. Did they need to grout behind the walls to address this issue?"

I asked the project engineer who worked on this job in the 1970s to respond to this comment and here's what he wrote:
"The 'standard' (i.e. customary) procedure in New York City soldier pile and timber lagging shoring applications was to put straw into the spaces between the boards. Not to keep water out but to prevent loss of soil which would lead to ground subsidence outside the excavation.
Water was to be controlled by drawing down the water table with the eductor and sand drain system. While our eductors worked successfully, a small amount of water flowed past the eductors at the top of the varved silt layer and leaked into the excavation. Also some water was kept in the very fine silt layers by capillary action.

Depending on location, the bottom of our excavation was on rock or the varved material which turned into mush with the slightest amounts of water. This made it impossible to put excavating equipment into the hole.
As a result, our soil excavation was done partially from street level with clamshell buckets and partially with equipment supported on the lower bracing (struts). In addition we installed pumps and eductors within the excavation and applied shotcrete to the face of the lagging in order to stop the infiltration.
This caused a reaction on the part of the Transit Authority (TA) because the lagging was not designed to resist a hydraulic head. This was true, but there was no head buildup by the minute amounts of capillary water. Still the TA ordered us to suspend operations and increase the number of struts.
Steel sheeting was required by the project specifications on the job south of us (i.e. the tunnel between 99th and 105th streets.) It was not required on our contract.
We estimated the job on the basis of piles and lagging partly because our review of the prebid information led us to believe that it could be done that way and partly in reliance on the TA's decision not to specify steel sheeting after having done so on the (almost) adjacent contract.
After we ran into difficulties on the project and filed our claims, the TA said that we should have bid on the basis of steel sheeting. We then checked with some of the other bidders. They had also bid on the premise of piles and lagging."

::


A Footnote:
This posting could not have been possible without the help of a project engineer who worked on this contract. He wishes to remain anonymous. He provided me with scanned copies of some of his photographs (35mm slides) that he took during the course of the construction. He also provided me with basic information about each photograph and answered my many questions.


Further Reading:

Second Avenue Subway Construction in the 1970s
The Launch Box - 9/21/2009
This posting includes a set of black and white "progress photographs" of the project. These photographs were taken for the Transit Authority by a professional photographer.

"Second Avenue Subway: Bumpy Road Ahead"
By Richard Cohen
New York
- 2/8/1971

Crimmins Contr. vs. City of NY
Thomas Crimmins Contracting Co., Inc., and Cayuga Construction Co., a Joint Venture, Respondent, v. City of New York et al., Appellants and Third-Party Plaintiffs, et al., Third-Party Defendant.
74 N.Y.2d 166 (1989)
Court of Appeals of the State of New York.
7/13/1989


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Update: 10/1/11

Recently I came across this link, "Second Avenue Subway, Harlem Edition", by a group called The LTV Squad, that includes a set of recent images that are apparently the same tunnel in Harlem. I've posted the link here for viewers who may be interested in seeing what these tunnels look like today.

My posting of this link here does not in any way indicate that I endorse the photographers' activities, since it would seem clear that all of the images were taken while trespassing on MTA property.


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

Sandhogs resurface and the 96st Subway entrance begins
By Ben Thompson
Thompson's Travels
7/25/11

"Trying to Plug Big Budget Gap,
MTA Asks City to Pay for 2nd Avenue Subway"

By Jim O'Grady
WNYC News - 7/30/11

Second Avenue Subway Task Force Meeting Request for August 10th
Letter from MTA Capital Construction to Community Board 8
7/29/11
This letter prompted the cancellation of the CB8 Second Avenue Subway Task Force meeting that was scheduled for August 10th. Most of the letter deals with air quality issues in and around the 72nd Street station cavern work location.

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Deep Below Park Avenue, a 200-Ton Drill at Rest
By Michael M. Grynbaum
The New York Times - 7/24/11
This article isn't about the Second Avenue subway. I've included a link to it here because I found it to be particularly interesting.

Michael Grynbaum's story details the recent massive entombment, 14 stories under Park Avenue, of one of the TBM cutterheads used on the MTA's East Side Access project.