under Construction, the Second Avenue Subway

New York City's newest subway line working progress 


by : pgopta
# Monica Bradley, Scientific American's photo editor, and photographers Jeremy Floto and Cassandra Warner. 




There are view of Subway Tunneling work on construction. 

Fresh Air

The Worker needs fresh air down the tunnel, its carrying by giant air channel hanging up the tunnel ceiling.

Safety First
Every worker who gets in the tunnel is always monitored by changing their tag status into red, that previously blue. So, in the emergency situation they will always known. 

Tools and Seepage
Working hard need a powerful tools. There are Seepage on the wall. Its happen all the time cause the tunnel is below the water table. Pumping is the simple things to do.

Train Track
The track showing us that they need to transport the material to/ from inside the tunneling. Just a temporary structure. The real track for subway will be installed after they complete the tunneling work. 

World Trade Center Vehicle Security Center

by : Nicholson Company

• Location: New York, NY
• Owner: Port Authority of New York & New Jersey
• Technique(s) Utilized: Anchors, Diaphragm Walls, Jet Grouting, Secant Pile Walls, Micropiles
• Subsurface Conditions: Fill over sands and silts with till and/or decomposed rock over hard Manhattan schist bedrock
• Approximate Key Quantities: Diaphragm Wall - 40,000 square feet, Jet Grout Columns - 122
  Secant Pile Wall - 10,000 square feet, Slurry Wall - 6,000 square feet, Tieback Anchors - 285 

 

A decade after the devastating attacks on the heart of New York, the city continues the remarkable process of rebuilding the former site of the World Trade Center (WTC). Nicholson has been at the site and an integral part of the process from the beginning – from securing the area for search and rescue to being a part of the extraordinary and ongoing reconstruction work, which began in 2006.

PROJECT BACKGROUND

With the opening of the World Trade Center Memorial, slated for September 11, 2011, downtown New York City will become more congested than ever. On a normal day in the city, 200 commuter buses make daily stops in the Financial District, in addition to the dozens of tour buses canvassing the streets at any given time. With the opening of the WTC Memorial, it is estimated that an additional 200 tour buses will be making their way into the city on a daily basis. The additional buses compound an ongoing problem for New York City in that parking is at a premium, but they also echo the security concerns that have become a reality for the city's visitors and tenants since the attacks. In response to these issues, the Port Authority of New York and New Jersey commissioned the construction of the World Trade Center Vehicle Security Center and Tour Bus Parking Facility (VSC.) The VSC will function as part of the comprehensive, state-of-the-art plan for the screening of buses, trucks and cars entering the WTC and its parking facilities through the basement level. This below-grade structure requires a five-story deep basement with connecting ramps into the West Bath tub Area, which includes the 9/11 Memorial Site and Museum, the new Freedom Tower and the PATH subway line.

THE WORK
Nicholson has served an integral role in the construction of the World Trade Center Vehicle Security Center and Tour Bus Parking Facility (VSC).

The initial scope of Nicholson's work at the VSC, which was carried out in JV with EE Cruz, was to create a water-tight excavation, measuring 220 ft. by 450 ft. and reaching a depth of 60 ft. The first phase of the project included the installation of a 40,000 square foot diaphragm wall with 210 tieback anchors, as well as 160,000 cubic yards of bulk excavation, 10 jet grout columns, 320 rock bolts, 6,000 square foot temporary slurry wall, cast-in-place concrete, compensation grouting and pipe struts.

The diaphragm walls installed by Nicholson will form the southern part of the VSC, which will include a parking area to accommodate the increased number of tour buses entering the WTC.

In March of 2011, Nicholson began working for Yonkers Construction on the earth support and water cutoff phase of development, which includes 10,000 square feet of secant pile wall, 75 tieback anchors, 15 micropiles (200 tons) and 122 jet grout columns with lengths ranging from 15-40 feet. 

THE RESULT

Working in the heart of one of the most heavily populated cities in the world creates a unique and ongoing set of challenges. Nicholson's exposure to those challenges, beginning with the initial excavation of the site following the attacks, and continuing on through the latest phase of the VSC's development, has been a critical success factor.

The VSC, which is slated to open in 2012, will contain approximately 50 tour-bus parking spaces in total, which should effectively accommodate the additional tourist traffic entering the newly rebuilt WTC.

International Green Building Conference 2011

We are pleased to invite you to join us at the 

International Green Building Conference 2011 (IGBC 2011)

that will be held from 13 - 16 September at Suntec Singapore.

As part of the Singapore Green Building Week, this biennial event, organised by the Building and Construction Authority of Singapore, will be held alongside the annual BEX Asia 2011 exhibition.

The inaugural IGBC in 2009 was attended by close to 1,000 participants from

23 countries world-wide, while BEX Asia 2010 attracted

over 7,000 participants.

"Build Green. Act Now."

Green. Act Now." will build on its previous success by continuing to focus on 

hot topics such as tropical architecture and green building case studies. 

In addition, it will examine new topics with emphasis on sustainable construction, 

buildings of the future as well as sustainable operations and maintenance.

Featuring Distinguished Speakers and Industry Leaders

You will get the opportunity to interact with fellow industry leaders and practitioners through 

the various workshops and networking events. Specially designed Green Mark Tours will 

allow you to visit outstanding BCA Green Mark projects while providing you with unique 

and practical learning experiences.

Meet 'Brenda,' the Capitol Hill tunneling machine

Sound Transit tunneling work to start in next few weeks

By SCOTT GUTIERREZ, SEATTLEPI.COM STAFF

Published 12:34 a.m., Monday, June 13, 2011

Tunneling for Sound Transit's subway from Capitol Hill to downtown is expected to start in the next few weeks.

Photo: Scott Gutierrez/seattlepi.com / SL

In the next few weeks, Sound Transit plans to start tunneling through Capitol Hill as the next phase of construction starts on a subway from downtown to the University of Washington.

A 21-foot diameter boring machine nicknamed "Brenda" will do the work. Brenda was named as a tribute to the project manager's wife.

"He named the last tunnel boring machine Mary-Margaret, which was the name of his mother," said Glen Frank,  quality control manager for the contractor, JCM U-Link Joint Venture, formed by Jay Dee Contractors of Michigan; Frank Collucio Construction Company of Seattle; and Michaels Corporation of Wisconsin.

 

"Brenda," a 21-foot diameter tunnel boring machine, will dig Sound Transit light rail tunnels from Capitol Hill to downtown.

Photo: Scott Gutierrez/seattlepi.com / SL

On Friday, Sound Transit took reporters for a tour of the future Capitol Hill light rail station at Broadway and East Denny Way, on the northwest corner of Cal Anderson Park. Right now, it's a cavernous concrete shell about 70 feet deep. Brenda waits at the bottom like a giant mechanized worm.

Brenda is more than 300 feet long and weighs more than 800,000 pounds.

"Basically the tunnel boring machine is designed as very simple submarine," Frank said.

The machine will burrow through 40 feet of dirt per day until it reaches the Downtown Transit Tunnel at Pine Street, where it will be disassembled, loaded onto trucks, and hauled back to the Capitol Hill site. Then, it will bore the second tunnel.

The tunnel boring machine at Capitol Hill is 330 feet long.

Photo: Scott Gutierrez/seattlepi.com / SL

That's the last time the machine will see the light of day. Once the second tunnel is completed, crews plan to remove the cutter-head and the machine's guts and entomb the outer shell within the tunnel's concrete lining beneath Pine Street.

Tunneling will last for the next 12 to 18 months. It will be a 24-hour operation.  Residents aren't likely to hear the tunneling itself, although there will be trucks hauling dirt away from the station site.

So far, 800,000 cubic yards of dirt have been excavated to build the station's box. The tunneling machine will dig from 15 feet below the surface to about 130 feet.

The boring machine is equipped with an array of sensors and instruments to monitor the amount of dirt removed. Crews will watch the data closely to avoid over-excavation. The machine has a 10-person crew, with the operator working from a control center about 60 feet from the cutter-head.

This 70-foot-deep concrete box will be the future light rail station on Capitol Hill.

Photo: Scott Gutierrez/seattlepi.com / SL

"There is potential for some settling. We anticipate some settling, but it is very small. If we do what we're planning to in terms of monitoring performance of the machine, we shouldn't have any problems," said Rick Capka, construction manager.

Sound Transit encountered a number of problems with tunneling through Beacon Hill for Central Link light rail, which opened in 2009. Soils settled after construction by the contractor, Obayashi Corp.,  and opened up voids under several residents' properties due to over-excavation. A 21-foot-deep void opened in one resident's yard and Sound Transit wound up purchasing the property for $400,000, with the total price of the mitigation work reaching close to $4 million.

With lessons learned from the other hill, this time will be different, Sound Transit says.

"It is different in that we have more oversight," Capka said. "We also have different technology."

Rick Capka, construction manager at the Capitol Hill light rail site, explains how the tunnel boring machine works.

Photo: Scott Gutierrez/seattlepi.com / SL

The excavated dirt is carried out on a conveyor belt as the machine presses onward. Massive prefabricated concrete rings with rubberized gaskets are left in place to form the tunnel. Brenda is an "earth pressure balance" tunneling machine, meaning excavated dirt is used to fill a chamber behind the cutter-head to counterbalance the pressure it's up against as it grinds away.

Two other tunneling machines will start from the University of Washington to build the segment between campus and Capitol Hill. Together, they'll complete a 3.15-mile, $1.9 billion line. It's expected to serve an additional 70,000 riders.

The 21-foot cutterhead.

Photo: Scott Gutierrez/seattlepi.com / SL

The future Capitol Hill light rail station.

Photo: Scott Gutierrez/seattlepi.com / SL



Read more: http://www.seattlepi.com/local/transportation/article/Photos-Light-rail-tunneling-soon-to-start-on-1419575.php#ixzz1PD4FXZ81

Sinkhole Opens in Beijing Road, Swallows Truck

by: National Geographic--Daily News

Sudden Sinkhole

Photograph from AFP/Getty Images

Onlookers in Beijing, China, keep a safe distance from a giant sinkhole that opened in the middle of a busy street last Tuesday, swallowing a truck. Several news reports say the sinkhole formed above a tunnel being dug for construction of a subway line. (See pictures of a huge sinkhole in Guatemala City.)

But Chinese engineers urged caution in jumping to conclusions: "It could have resulted from multiple causes," Wei Jinglian, a senior engineer from the Beijing Institute of Geology, told China's Global Times. "Water leakage from old pipes underground may have softened the soil," Jinglian said, "or there has been too much pressure frequently on the same section of road."

Mining and construction activities can weaken the subsurface and cause sinkholes to collapse, said Mike Hoyal of the Tennessee Division of Geology. But sinkholes can also form naturally when water-saturated soil becomes too heavy, causing the roofs of existing voids and caves in the ground to collapse.

In addition, acidic rain or groundwater can enlarge a natural fracture in a limestone bedrock layer to form a sinkhole. The water "dissolves out the calcium carbonate in the limestone and forms fractures," Hoyal said. As the crack gets bigger, the topsoil can gently slump, exposing the sinkhole to the world.

—Ker Than

Published May 3, 2011

Narrow Escape

Photograph from AFP/Getty Images

The tail end of a truck protrudes from debris inside the Beijing sinkhole on April 26. According to news reports, the driver and a passenger jumped out of the vehicle before it sank into the hole. Both people were only slightly injured.

ngineers typically conduct foundation studies to test the stability of the ground at a site before beginning any major construction, such as a city highway. But "that's only been true within the last few decades," Hoyal said. It's possible, he said, that the Beijing sinkhole formed after a new roadway was built on top of an older road that did not have foundation studies done before its construction.

Based on the pictures, Hoyal estimates that the Beijing sinkhole is about 25 feet (7.6 meters) wide and about 35 feet (10.6 meters) deep.

"That's a pretty impressive sinkhole," he said. (See pictures of sinkholes around the world.)

Published May 3, 2011

Road Repairs

Photograph from AFP/Getty Images

Construction crews begin to repair the giant Beijing sinkhole, which formed the night of April 26.

It can take thousands of years for the pit of a sinkhole to form naturally beneath Earth, Hoyal said, but the collapse of the ground above can be instantaneous. Over time "the soil cover and limestone cap rock [above a sinkhole] get weakened, and all of a sudden the bottom drops," he said.

Published May 3, 2011

Filling in the Gap

Photograph from AFP/Getty Images

Excavators work to repair the Beijing sinkhole in a picture taken last week.

Weather can contribute to the formation of sinkholes, Hoyal said. For example, during an extended drought, natural clays in the ground can form cracks, shrink, and become "less sticky."

When rain falls on the region again, or if underground water seeps up toward the surface, "the clays in the soil expand and lose their cohesive properties, and the soil becomes unstable ... and it causes structures to fall," Hoyal said.

Published May 3, 2011