Tuesday/ Bertha sees daylight

Yay! The tunnel boring machine called Bertha, digging the State Route 99 tunnel under the city to replace Seattle’s Alaskan Way Viaduct, emerged today into the sunlight.  The tunnel is 1.7 miles (2.7 km) long.  Digging started four years ago in April 2013, but came to a halt in December 2013 when damage to the the main bearing was sustained.  It would be two years, until December 2015, before digging could resume.

So .. now the tunnel is dug, but it will still take until early 2019 before the current above-ground section of State Route 99 can be moved below ground, by using the tunnel.

The moment the tunneling machine broke into the end wall. What happens next? Well, the braces in the disassembly pit will be removed, the tunneling machine pushed forward so that the cutter head can be removed. then the rest of the machine will be taken back through the tunnel to the starting point. (The crane that can lift the very heavy machinery, is located).

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