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Breakthrough! Bertha TBM Completes Alaskan Way Viaduct Tunnel in Seattle PDF Print E-mail
Written by Randy Post   
Tuesday, 04 April 2017 22:29
Seattle Tunnel Partner workers roosting in the spokes of the Bertha TBM after the breakthrough

After tunneling 9,270 feet under downtown Seattle, the Bertha tunnel boring machine finally broke through at the north portal yesterday. The breakthrough marks a major milestone in the project to replace the seismically deficient SR-99 Alaskan Way Viaduct. The 57.5 foot diameter machine started tunneling in July of 2013, and I was fortunate enough to take a tour of it shortly after that. The Seattle Tunnel Partners team ran into some major problems in January of 2014 when they encountered an 8 inch well casing which damaged a seal inside the cutterhead which ultimately required the creation of an access pit and the replacement of the entire cutterhead.

Although the tunnel drive took two years longer than anticipated, and some significant cost overruns, this remains one of the most amazing engineering achievements of our lifetime! I highly encourage you to check out the article I wrote about the tunneling project and all of the interesting geotechnical features that go along with it after my tour of the project site. And you can check out my photos from the tour at the GeoPrac.net Facebook page. While you are there, give us a like! [Source: Read the full blog post from WSDOT. Image: GeekWire / Kevin Lisota]

 
Norway may build the world's first tunnel for ships PDF Print E-mail
Written by Randy Post   
Wednesday, 29 March 2017 23:04
Rendering of proposed ship tunnel in Norway

If Norway's Stad Ship Tunnel gets approved, it would be located on the Stadhavet Sea, an area known for heavy winds and hurricanes. Stormy weather makes it almost impossible for ships to travel in the area. Vessels often wait for hours or even days before it becomes safe enough to cross. A study has been performed by the Norwegian Coastal Administration (NCA), and their findings are scheduled to be released this May. If approved by the Norway Department of Transport, construction could begin as early as 2019. [Source: View more info at Business Insider via AGC SmartBrief. Image: Norwegian Coastal Administration via Business Insider]

 
Underneath Seattle: Working Under Pressure to Keep Bertha Moving PDF Print E-mail
Written by Randy Post   
Wednesday, 08 March 2017 22:48

Every tunneling machine needs its cutting tools replaced every now and then. But the challenge is keeping a giant machine sharp while a wall of waterlogged earth looms in front. Welcome to the world of hyperbaric interventions, where crews used compressed air to stabilize the ground and safely complete this high pressure work. This video takes you 200 feet underground for a rare look at hyperbaric work inside Seattle’s SR 99 tunneling machine, Bertha. [Source: WSDOT YouTube Channel. Image: YouTube]

 
URETEK Rehabilitates Prison Rec Hall PDF Print E-mail
Written by Randy Post   
Tuesday, 31 January 2017 14:46

An aging prison building in Fort Worth, Texas had seen areas of settlement as much as 7.5 inches inside the building. URETEK successfully implemented their URETEK Method to lift the sunken slabs and stabilize the floor of the Prison's Rec Hall. Check out the video below or visit URETEK's blog post for more info. [Source: URETEK ICR YouTube Channel. Image: YouTube]

 
The Building Blocks of the SR 99 Tunnel PDF Print E-mail
Written by Randy Post   
Sunday, 02 October 2016 15:16

The tunnel liner that is being placed by the Bertha tunnel boring machine consists of precast concrete segments. This video by the WSDOT shows how they are made at the casting yard, and what Bertha does with them once they get delivered to her where the action is happening. The finished tunnel will consist of over 14,000 of these precast segments! [Source: WSDOT YouTube Channel. Image: YouTube]

 
Nicholson Awarded Secant Pile Contract for St. Louis CSO Facility PDF Print E-mail
Written by Randy Post   
Sunday, 28 August 2016 22:02
Anchored secant pile wall in New York

Nicholson Construction was recently awarded a secant pile wall contract for the Maline Creek combined sewer overflow (CSO) project in St Louis, Missouri. Their scope of work will include 78 880-mm (~3-ft) piles to depths of 40 to 50 feet, 114 880-mm secant piles to approximately the same depth that will form a braced excavation. They will also install 4 seven foot diameter jet grout columns beneath an existing sewer to support it during excavation. [Source: More about the project at NicholsonConstruction.com. Image: Nicholson Construction]

 
Innovative Micropile Construction with DTH System PDF Print E-mail
Written by Randy Post   
Thursday, 23 June 2016 00:07
Micropile project in Northern Baltimore County

Our friends at Deep Excavation posted about an interesting micropile case study in Northern Baltimore County for a bridge replacement project. The project consisted of 38 Micro Piles; 7” OD X 38 ft. deep including a 7 ft. rock socket, installed on a 3/1 batter, load tested to 272,000 lbs. What caught my attention is the down the hole hammer system used for installing the micropiles. The system uses a ring bit to install the casing and allow the drill string to continue beneath the bedrock elevation to construct the rock sockets. [Source: Read more about this micropile project and see additional photos at Deep Excavation. Image: Deep Excavation]

 
Gotthard tunnel, world's longest, opens in Switzerland PDF Print E-mail
Written by Randy Post   
Monday, 06 June 2016 00:41
Crowds celebrate the opening of the Gotthard Base Tunnel

The Swiss and many other European dignitaries celebrated the opening of the World's longest and deepest tunnel last week, the Gotthard Base Tunnel, after 17 years of construction. The tunnel beneath the Swiss Alps is 57-kilometers long (35-miles long) reaching a depth of 2,300 meters (7,545 feet, almost 1.5 miles). The tunnel will create a high-speed rail link between northern and southern Europe. Trains will travel the tunnel, which runs between the towns of Erstfeld in the north and Bodio in the south, in only 20 minutes, reaching speeds of up to 250 kilometers an hour (155 mph), according to CNN. [Source: CNN via AGC SmartBrief. Image: Global Rail News]

 
Nicholson Begins Chemical Grouting Work on Wilson Classical High School in Long Beach PDF Print E-mail
Written by Randy Post   
Monday, 06 June 2016 00:26
Wilson Classical High School in Long Beach, CA

GeoPrac sponsor Nicholson Construction has started a chemical grouting project in Los Angeles at the Woodrow Wilson Classical High School to treat potentially liquefiable soils beneath the building. This $2 million project is part of a larger $21.1 million project to upgrade the infrastructure in the auditorium and adjacent areas. Nicholson will drill vertical, horizontal and inclined holes at depths of 14 to 24 feet beneath the structure and inject the chemical grout using a Tube-a-Manchette piping system. [Source: Read more about the project from Nicholson Construction. Image: Nicholson Construction]

 
Video: DeWind One-Pass Trenching - Hill AFB Contamination Project PDF Print E-mail
Written by Randy Post   
Sunday, 17 April 2016 22:21

This project video seems a few years old, but it's relatively new on YouTube and it's a fantastic case study of the slick method of installing groundwater interception trenches using DeWind's remarkable one-pass trenching technology. Hill Air Force Base in Utah had been using jet fuel ignited on a mock aircraft to train firefighters. The jet fuel had leached into the soil and was reaching the shallow aquifer. The DeWind technology was used to install a drainage trench to intercept the contaminated groundwater and pump it out for treatment before it reached the aquifer. This approach was several million dollars less costly than other alternatives they looked at. Project staff considered this method more likely to intercept the contamination than discrete wells spaced along the same alignment. [Source: DeWind YouTube. Image: YouTube]

 
World's Heaviest Monopile for Offshore Wind Turbine Foundation PDF Print E-mail
Written by Randy Post   
Monday, 11 April 2016 22:49
First of the 67 7.8m diameter, 82m long monopiles for Veja Mate offshore wind farm roll out

Check out this massive pile foundation for a wind turbine at the 402MW Veja Mate offshore wind farm. It weighs over 1,300 tons (2,866 kips) and is 7.8 meters in diameter (25.5 ft) and 82.2 meters long (270 feet). The wind farm will consist of a total of 67 6MW turbines founded on giant monopiles like this. According to Offshore Wind, the Veja Mate OWF is located 95 km northwest from the island of Borkum in the German North Sea. When fully operational in 2018, the farm will produce over 1.6 TWh of electricity annually for 400,000 households in Germany. [Source: Offshore Wind. Image: Offshorewind.biz]

 
Bertha Demo Period Done, Resumes Mining PDF Print E-mail
Written by Randy Post   
Monday, 14 March 2016 23:27
Bertha's scheduled maintenance stop

The Bertha tunnel boring machine has resumed chewing away beneath Seattle after a 'suspension for cause' order from WSDOT shut it down in January following two safety incidents. The BTM began tunneling with some conditions in place late in February, and those conditions were lifted when the demonstration period ended on March 7. Bertha has now reached her next scheduled maintenance stop, having tunneled a total of 1,560 feet. [Source: WSDOT Alaskan Way Viaduct Replacement Project Page. Image: WSDOT]

 
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