Construction has started on the tunnel boring machine launch pit for the WSDOT SR 99 Tunnel Project (Viaduct Replacement). The 420 foot long pit is being constructed using secant pile retaining walls, with 2 rows of 5 foot diameter piles, all around 90 feet deep. Based on the fantastic photos on WSDOT’s Flickr Page, it appears that Malcolm Drilling is performing the secant pile wall work. [Source: The Seattle Times via ASCE SmartBrief. Image: WSDOT Flickr]
Related Articles
FHWA NHI 2009 MSE Wall Manual
[Disclosure] NCS Consultants is the employer (day job) of Randy Post, the owner of this site. [/Disclosure]
Geotechnical engineers who encounter MSE retaining walls or Mechanically Stabilzed Earth Walls are undoubtedly familiar with the FHWA NHI manual on “Mechanically Stabilized Earth Walls and Reinforced Soil Slopes”. This manual, along with the NCMA manual that is used for non-transportation projects, is virtually the bible for MSE wall design. In late summer/early fall of 2009, a revised version of this manual will hit the streets. Read on for more details.
Video: Inside tunneling under the Alaskan Way Viaduct
From WSDOT’s video description: After nearly a week of tunneling under the Alaskan Way Viaduct, crews are steadily continuing Bertha’s underground drive towards downtown Seattle. This video gives you a behind-the-scenes glimpse into how the […]