Over 200 buildings will receive some form of geotechnical and geostructural monitoring around the Highway 99 tunnel in Seattle, better known as the tunnel that will replace the Alaskan Way Viaduct. A Seattle Times article listed some of the technologies being employed, such as automated survey machines, crack meters, extensometers, tiltmeters, liquid level sensors, inclinometers and crack gauges. A total of roughly 700 devices will be deployed by the time the tunneling starts this summer, a $20 million program. The project team will also be using interferrometric synthetic aperture radar or INSAR techniques to supplement the traditional surveying methods as they watch for subsidence and ground loss problems along the tunnel route. This satellite-based method is accurate up to 1/8 inch, but has the advantage of being able to cover a larger area than just using the survey prisms at particular points. [Source: The Seattle Times via ASCE SmartBrief. Image: KEN LAMBERT / THE SEATTLE TIMES]
The New York MTA is in the midst of a “golden era” of tunneling for the New York subway. Three separate mega-projects are currently underway totaling some $15 Billion: The Second Avenue Subway, The East Side Access Project (which features the new Grand Central Terminal), and The Number 7 Subway Line Extension Project. The short video below was published by the NY Post and included in an AP Article. It is tantalizingly short, but gives a great perspective on what the underground construction project at Grand Central looks like and a sense of the scale…the amazing huge caverns being constructed. The article says that from underneath Grand Central Terminal alone, the construction crews have removed enough material to cover Central Park almost a foot deep!
New York's famous transportation icon, Grand Central Station (more properly Grand Central Terminal) celebrated the 100th anniversary of it's opening on February 2, 2013. This rail terminal is more than just a means of travelling from point A to B, but it is a romantic, and grandiose metaphor for the hustle and bustle of American life. While the structure is definitely a cultural and architectural monument, it is also an engineering marvel, a fact recognized in 2012 by ASCE when it named it a National Civil Engineering Historic Landmark.
While the centennial of the GCT is being celebrated, a new project is taking shape approximately 90 feet below the existing tracks. The East Side Access project (ESA) will provide a new connection from the Long Island Rail Road (LIRR) to GCT. This project will help...
Specialty geotechnical drillers Crux Subsurface, Inc. of Spokane, WA has been working on a challenging project in a residential neighborhood in Bellevue, Washington. Their work is in support of a King County project to upgrade wastewater conveyance system currently served by the Sunset and Heathfield Pump Stations in Bellevue. Crux was selected for the job because of their experience in working in restricted and congested areas and because of anticipated difficult core recovery. [Source: Crux. Image: Crux]
The Devil's Slide Tunnel Project was originally scheduled to open at the end of 2012, but it has been delayed slightly to an early 2013 opening. If you look at some recent photos, you can hardly tell that there is anything left to finish. I've been following this project since it started, since to me it represents the essence of geoengineering, with important roles played by geotechnical engineers, geological engineers, hydrogeologists, and of course geotechnical contractors and tunneling specialists. I thought it would be interesting to list a few of the posts I've written about the project over the years and present a bit of information I only recently learned. Click through for more. [Image: kxyoung on Flickr]
Groundforce supplied ten hydraulic struts to support the excavation at a commercial development known as Merchant Square in West London. Six of the struts were the monsters pictured, 500 tonne (1,100 kip) capacity, 49 m (160 feet) long, the largest struts that Groundforce makes. These struts were able to span the entire width of the excavation without intermediate support. Check out the cool time-lapse video below to see the entire sequence of excavation. [Source: Groundforce via NCE. Image: Groundforce]
Time Lapse Video of Merchant Square Deep Excavation
The cover story of the November 2012 Civil Engineering Magazine is about the incredible cantilevered pedestrian walkway known as the Cliffwalk, located some 300 feet above the Capilano River Valley in Capilano Suspension Bridge Park near Vancouver. This amazing structure is a feat of rock engineering as well as structural engineering, fabrication and construction (among other things). Famed geological engineer Duncan Wyllie, who literally wrote the book on Foundations on Rock, was the rock engineer on the project. The geotechnical engineers rappelled along the cliff face to perform structure mapping. The rock bolts in the granite cliff were up to 18 feet long, and a total of 1,673 feet of rock bolting was used. The geotechnical design also had to consider rockfall potential above the walkway. The excellent video below shows the entire process of construction of the Cliffwalk...it's well worth the 6 or 7 minutes! [Source: Civil Engineering Magazine. Image: Capilano Suspension Bridge Flickr Stream]
Video of the Making of the Cliffwalk at Capilano Suspension Bridge Park
This is a great video showing the application of ground freezing to deep excavations in unstable soil and high groundwater table. It’s also a nice overview of the reason the Hetch Hetchy project was undertaken, to replace aging San Francisco Bay area water supply infrastructure that would not survive a major earthquake on the Hayward Fault or San Andreas Fault. I tried to find the name of the ground freezing contractor…I think it was SoilFreeze based on a quick shot of a logo on some equipment. Can anyone confirm? The vertical access shaft being constructed in Newark will be where the TBM will be disassembled and removed.
The Kingdom Tower to be built in Jeddah, Saudi Arabia will be 1,001 meters tall when completed in 2018. It will be the first building taller than 1-km and 173 meters taller than the Burj Khalifa in Dubai, the current tallest building in the world. NCE reports that Bauer has won the â‚¬25M (US$32M) foundation construction contract consisting of 270 drilled shafts of 1.5 or 1.8 m diameter and 110m in length. They also report that the original design was for a 1.6 km tall structure, but the geotechnical investigation found that the site would not support such a structure and the plans were scaled back to the current planned height. [Source: New Civil Engineer. Image: New Civil Engineer]
To keep the loose soils beneath a planned hospital from liquefying and damaging the foundations during the design earthquake, Hayward Baker stabilized the site by performing wet soil mixing. In addition, HB installed tie down soil anchors inside soil mix columns to counterbalance the building seismic uplift forces. The team worked tirelessly to balance safety and production with stringent design and QC requirements. Learn more on their website, www.haywardbaker.com
California Governor Jerry Brown announced this summer that the state will move forward with plans for two multi-billion dollar water supply tunnels. Twin 56-km long (35 miles) tunnels will be constructed to convey water from the Sacramento River south to an existing aqueduct that serves the San Joaquin Valley and Southern California. [Source: World Tunnelling. Image: Rich Pedroncelli via KTVU.com]
Geotechnical consulting firm Shannon and Wilson based in Seattle, Washington was involved in the foundation engineering for a 360 ton sculpture by Michael Heizer at the Los Angeles County Museum of Art (LACMA). The giant granite boulder sits over a depressed ramp to the La Brea Tar Pits. The sculpture is entitled 'Levitated Mass'. I'm reminded of a quote by Richard L. Handy:
Virtually every structure is supported by soil or rock. Those that aren't either fly, float, or fall over.