The $2B tunnel project for the replacement of the Alaskan Way Viaduct crossed a major hurdle with the approval of a document that will allow the environmental studies for the project to continue. Mayor McGinn’s position is that more time was needed to evaluate the document and he was concerned that a tunnel option was a predetermined outcome of the study. He went even farther by alleging that WSDOT and the City Council conspired to ‘violate the city charter [regarding separation of powers] and state law’. Nevertheless, Councilman Conlin signed the document allowing WSDOT to continue their progress towards a construction contract in early 2011. [Source: Seattle Times Newspaper. Image: Seattle Times]
The Claremont tunnel beneath the Berkeley Hills on the east side of Oakland is a water supply tunnel that serves over 800,000 customers in Richmond, Oakland, San Leandro and neighboring communities. One of the unique things about the tunnel is that it crosses the active Hayward Fault. Most of the time when you talk about designing for earthquakes youâ€™re talking about designing to withstand the seismic forces. In this case, the designers needed the water transmission tunnel to withstand up to 7.5-ft of offset due to fault slip and still maintain a minimum level of service. (Photo credit: Sue Bednarz, Jacobs Associates, Inc. by way of Civil Engineering Magazine)
This post describes the relatively recent Claremont Tunnel Seismic Upgrade Project as reported in Civil Engineering Magazine (May 2008, v. 78, no. 5, pp 58-63, 96-97).
A stretch of tunnel on Eastbound I-70 in scenic Glenwood Canyon Colorado was closed last March because of a 70-foot long crack in the ceiling. Since then the two-lane westbound bore has been handling both eastbound and westbound traffic while repairs to the damaged segment were undertaken. This project has a little of everything: heavy excavation, rockfall, slab reinforcing, geofoam, and even geogrid! Read on for more details, a map and photos. (Photo by Concrete Works Of Colorado)