Photo Courtesy of WSDOT The 57.3-ft-dia "Bertha" is currently the world's largest tunneling machine. Now being shipped to Seattle in segments, she will begin excavation for the new state Route 99 this summer. Related Links: Here Comes Bertha Alaska Way Viaduct Proceeds Despite Mayor's Opposition When the 57.5-ft-dia earth-pressure-balance tunnel-boring-machine called Bertha reaches Seattle from Japan next month, it will make its debut at a 400-ft-long, 80-ft-wide and 80-ft-deep launch pit that crews have been toiling on for months. The 6,700-ton, 326-ft-long tunneler's arrival will be a key milestone in the $3.1-billion, 12-project program to replace the Alaskan Way Viaduct.The
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.