Brightwater tunnel inches through toughest stretch toward finish

Worker clears sludge from Brightwater TBM

Worker clears sludge from Brightwater TBM

The massive 13-mile wastewater tunnel project known as Brightwater is approaching the final stretch of tunneling, but perhaps the most difficult. This portion of the project has already claimed one contractor’s slurry TBM and put the $1.8B project behind schedule. The current JV contractor, Jay Dee and Coluccio have successfully tunneled 4-miles of a different segment of the project and have modified their earth pressure balance TBM for the center segment. According to project manager Greg Hauser:

We’re doing things that haven’t been done before. Taking an earth-pressure-balance machine to these pressures isn’t done…

The article goes on to describe the difficult, high pressure conditions the contractor is likely to encounter as well as the ongoing lawsuit regarding the stuck TBM and the difficulties of the original contractor. [Source: Seattle Times Newspaper via AGC SmartBrief. Image: Seattle Times]