WSDOT Says September Tunneling Date Only "Tentative"
WSDOT says the projected September date for restarting tunnel construction is only "tentative." "We want to make sure [a Bertha breakdown] doesn't happen again."
The state project manager for the downtown deep-bore tunnel construction project, Todd Trepanier, said today that Seattle Tunnel Partners' project manager Chris Dixon's prediction, back in February, that tunnel construction could be underway as soon as September, was only a "tentative" projection that came before the tunnel construction group had a chance to sit down with the company that manufactured the stalled tunnel-boring machine, Hitachi-Zosen.
"That [September 1] was a date that was given by STP and we’ve always seen that as a tentative date, to guard against expectations that this thing was going to be up and running in a month," Trepanier said. "We are giving them that time because they have the contractual right to do that," and to enable them "to fully understand what has happened so that they can address it completely. That’s why they’re not just jumping right out and trying to get this machine running right away."
"We only want this repair to be done once."
The construction that will be required to fix the tunnel machine is itself no small matter. It involves "digging a big hole in the ground," in Trepanier's words, 120 feet deep and about 83 feet in diameter, and inserting a ring of seven-foot-diameter concrete pillars, which will touch at the edges, to completely surround the hole. Once that's built, STP will turn Bertha back on and drill into the concrete wall, allowing workers to access it from above and remove the cutterhead and, ultimately, fix the busted seals (and potentially the bearing itself, if that also turns out to be damaged).
(Bertha, Trepanier explained, "can mine right now—it just overheats very, very fast.")
Although Trepanier emphasized that WSDOT "only want[s] this repair to be done once," that raises an obvious question: But what if it has to be done again—and this time, not in the easily accessible part of Pioneer Square where it's currently stalled, but further north in the heart of downtown, where repairs will be much more complicated? Does STP have a contingency plan?
Trepanier said he didn't know the exact answer—STP's Dixon, who was supposed to be on today's conference call, canceled at the last minute—but said that because STP has agreed to build the contract for a fixed price, "there really is no one that has more at stake in making sure that this machine does not break down again than STP. They’re fully motivated, this is their area of expertise, and they’re the best in the world at it. This [first] 1,500 feet was meant to do the test run and make these type of adjustments."
Editorializing here, but once you're digging a 120-foot-deep, 83-foot-wide pit and filling it with concrete pillars, it seems to me that you've gone a bit beyond the realm of "adjustments" and into the realm of "major, potentially project-delaying construction."