Bertha, Seattle’s once-beleaguered tunnel boring machine, makes its final dash to the finish line this week, four years and two miles from where it began.
As of Monday, Bertha reached the final 89 feet of a 9,270-foot dig, and 1,403 of its 1,426 concrete rings have been built and installed. The machine is expected to emerge into the light and a disassembly pit any day now near the intersection of Sixth Avenue North and Thomas Street. The exact date is “TBD,” according to Washington State Department…