Jan. 14 Bertha Update: Going Hyperbaric – Source: WSDOT This press release by WSDOT is fascinating, you should definitely check it out. It describes the hyperbaric intervention that deep see divers performed to try and determine what has impeded the progress of the Bertha TBM on the Alaska Way Viaduct Tunnel project. They describe how a bentonite mud is injected in front of the cutterhead to create a "membrane" so they could pump air into the excavation chamber to create an air bubble that the hyperbaric divers could work in. The air pushes the bentonite membrane into the soil face and holds back the soil and water. They use the screw conveyor to remove sufficient material from the excavation chamber so that the divers can work in the top half of the excavation chamber.
Jan. 21 Bertha Update: Initial Results of Hyperbaric Inspections – Source: WSDOT In this press release, WSDOT reported that as of January 21, STP divers had spent more than 35 hours under hyperbaric conditions inspecting the TBM cutterhead from inside the excavation chamber. They removed a piece of bent well casing, pieces of PVC pipe, and found a large boulder or piece of concrete in a cutterhead opening.
Jan. 23 Bertha Update: More Hyperbaric Work, No New Findings – Source: WSDOT In this press release, WSDOT mainly just updated the total tally of hours worked by the deep see divers in the TBM intervention at the cutterhead. As of January 23, they were up to 68 hours of work performed during 17 sessions.
Jan. 31 Bertha Update: Further evaluation required before tunneling can resume – Source: WSDOT Bertha moved forward about 2 feet on January 28 to test the cutterhead and build the next tunnel liner ring. STP crews observed abnormally high temperatures in some components, similar to what was observed during the original stoppage on December 6. The made adjustments, moved forward another 2 feet but the temperatures persisted. The analysis will continue.
Seattle Tunnel Partners released a new schedule this week for the repair of the damaged seals on the Bertha Tunnel Boring Machine. This revised schedule shows that the TBM won’t be digging again until March […]
On September 17, CALTRANS and Kiewit Pacific held a "tunnel excavation celebration" to kick off the start of tunnel construction on The Devil’s Slide Tunnels project on California State Route 1 (the Pacific Coast Highway) in San Mateo County between the town of Montara to the south and the city of Pacifica to the north. The project involves the creation of a separated two-lane road, one lane in each direction. This road will pass through twin tunnels, over twin bridges and connect with an existing non-separated two-lane road at each end. The new road will be approximately 6,500 feet long, made up of the roughly 4,000-foot twin tunnels, the 1,500-foot north approach road (which includes the 1000-foot parallel bridges), and the 1,000-foot south approach road. Upon completion, the new road will bypass geologically unstable portions of existing Route 1, sections of roadway subject to lengthy closures, high maintenance costs over the years, and risk of permanent failure. Thanks Geology.com for the heads up. [Read on for more background, photos, maps, and movies!] (Images by CALTRANS)
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…