Update, April 14: WSDOT confirmed in a blog post late Thursday that Bertha has started moving forward into the cradle as of 9 a.m. Thursday, beginning a much-shorter 80-foot journey to its final destination.
Although the tunnel-digging is through, the tunnel-boring machine still has some work to do. On its way out of the hole, Bertha will lay a few last tunnel rings.
After Bertha’s in position, crews will start disassembling the machine in up-to-20-ton truckloads.
Bertha may live on in some ways—parts may be salvaged for other projects—but much of the machine will be recycled.
We would say that Bertha will leave as quickly as it arrived, but considering that we were supposed to be driving through the tunnel by now, that would be not at all true.
Crews have spent the last several days removing the braces—including cleaning debris from Bertha’s breakthrough. It was a long process, but WSDOT has kindly posted a time-lapse video of the process, condensing the whole process into under a minute.
Original Post, April 13: Late Wednesday, Washington State Department of Transportation crews finished removing wall braces standing between tunnel-boring machine Bertha and the pit where it will eventually be disassembled.
The Alaskan Way Viaduct replacement tunnel boring machine—nicknamed after former Seattle mayor Bertha Knight Landes—broke through the concrete wall of the disassembly pit last week.
In images and video of the breakthrough, the wall braces holding everything together are clearly visible. As of last night, WSDOT’s time-lapse camera shows the machine’s unobscured cutterhead.
Now that the braces are no longer in the way, the machine still has to move forward into position for disassembly.
This could take some time. WSDOT said that crews could start moving the machine into position Thursday.
At the time of Bertha’s breakthrough, WSDOT said it would take several days to remove the braces, but it could be weeks until the machine is in position.
With Bertha’s work done, focus has shifted to the crews filling in the SR 99 tunnel behind it. According to WSDOT’s most recent update released April 7, crews have completed at least 4,965 feet of southbound roadway out of 9,270.
WSDOT estimates the tunnel should be ready for traffic—and that the Alaskan Way Viaduct will come down—in 2019.
- @BerthaDigsSR99 on Twitter [WSDOT]
- Bertha breaks through: Watch the tunnel boring machine’s cutterhead emerge [CS]
- Alaskan Way Viaduct Replacement Project Schedule [WSDOT]
- Interior Structures Weekly Report [WSDOT]
- April 13 project update: Bertha's next move [WSDOT]
- Life after Bertha: Focus shifts from mining to other tunnel work [WSDOT]