Contractors building two segments of a 13-mile-long sewage conveyance tunnel near Seattle have devised plans to fix in place two stalled tunnel-boring machines that had been working in poor soils and high groundwater pressure. The tunnel is a key portion of King County, Wash.’s $1.8-billion Brightwater wastewater treatment project. The rims of the cutter heads on the 17.5-ft-dia Herrenknecht slurry machines were damaged, allowing rock and boulders to get stuck, says Gunars Sreiders, King County project manager. The general contractor, the joint venture Vinci/Parsons RCI/Frontier-Kemper, first stopped tunneling in May and laid off about 160 employees. The second machine was
The market is generally healthy and steadily growing, and margins are up for large specialty contractors. Further, advances in design tools and owner demand for collaboration are giving subcontractors a seat at the table early on in projects.