Tag Archives: tunnel boring machine

News, Transportation

Seattle’s Tunnel Boring Machine Waiting on Concrete Liner Maker’s Next Move

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SR 99 tunnel liners (Photo: WSDOT)

[UPDATE: A spokesperson for Dragados USA says production of the tunnel liners resumed on Friday, July 12, 2013.]

Last week, the Tacoma News Tribune reported that the maker of the concrete tunnel liners for Seattle’s Viaduct replacement project, FPS EnCon, was coming apart at its joint-venture seams: “Tunnel liner builder FPS EnCon shows Frederickson workers the door.” The CEO of Denver-based EnCon United, Jim Sorensen, said that going forward his company would be a subcontractor on the project — FPS, a firm created by the Spanish construction enterprise Dragados USA, would manage the liners’ construction.

This development may be worrisome for tunnel-watchers familiar with Dragados USA’s performance in New York. Law 360 reported last year that:

The tunneling and concrete lining work awarded to Dragados and Judlau had been slated for delivery in February 2013. But the construction group informed the MTA in December that it was some 42 months behind schedule. Under the new agreement, the company will finish the tunneling but turn over responsibility for installing concrete linings to a new contractor.

Dragados’ new finish line on that project is this August. (This March, that East Side Access project was determined to be 10 years late and $4.4 billion over budget.)

While the EnCon reorganization is in progress, and subcontractors supplying the materials for the liners catch up to the $20-million plant’s demand, some 85 workers have been laid off. Though Sorensen admitted to some friction over the timeliness of payments from FPS, he denied that the layoffs were in response to a workers’ vote to join Laborers Local 252. (Non-union laborers get $10.50 per hour as a starting wage, $1.31 more than the state’s minimum wage of $9.19.)

In mid-May, the tunnel project was already a month behind schedule, with tunnel boring set to begin in July. Bertha, the $80-million, one-of-a-kind tunnel boring machine, spent longer in testing in Japan than anticipated after its main drive unit began making a strange noise and it had to be taken apart and reassembled.

The TBM requires a steady supply of tunnel liners to dig, as the liner segments form both the tunnel’s casing (keeping water and dirt out of the newly dug tunnel) and give the machine purchase for its push forward. Nine liner segments plus a “keystone” create about a six-foot-wide circle, 56 feet in diameter. About 1,000 of a total of 14,500 have been cast since February (the goal is 60 segments per day).

In Seattle’s case, neither the financing plan nor the timeline for removal of the Viaduct envision a worst-case prospect of significant delay and a doubling of costs. Tolling shortfalls have already created an ongoing controversy over who will pay, even if the project comes in on budget. State legislators continue to emphasize that the project will not get one dime in excess of that already allocated. Because it’s typical for large projects like this to take longer than estimated and come in over budget, the wisdom of a $3.1-billion project that simply replaces vehicular (or not, given freight restrictions and plenty of options for shunpikers) capacity will likely continue to be debated.

News, Transportation

Both of WSDOT’s Seattle Megaprojects Off to a Bumpy Start

Giant cranes lift the 57.5-foot-diameter cutterhead into place on the SR 99 tunnel boring machine in Japan. (Photo: WSDOT)
Giant cranes lift the 57.5-foot-diameter cutterhead into place on the SR 99 tunnel boring machine in Japan. (Photo: WSDOT)

For most of 2012, the Washington Department of Transportation was watchdogged by KOMO News because of cracks found in new pontoons for the new 520 bridge. Now the Seattle Times‘ Mike Lindblom reports that Bertha, the 7,000-ton tunnel boring machine, purpose-built for digging the SR 99 tunnel beneath Seattle, sustained damage during its initial testing in Japan.

A January 23, 2013, update from WSDOT read, “She was performing well until last week, when crews discovered that something wasn’t quite right with her main drive unit, which rotates the cutterhead. It appears there was insufficient clearance between a rotating and stationary portion of the main drive unit, which resulted in damage to some of its components.”

Said Lindblom: “Testing was to be finished Dec. 25. As of this week, Hitachi Zosen crews in Osaka are disassembling and diagnosing the drive system.” (Sidebar: Although Bertha is, for a little while, the world’s largest-diameter TBM, it’s not a Big Bertha reference; the machine is named for Bertha Knight Landes, Seattle’s only female mayor.)

Bertha’s Twitter account has so far made no reference to its need for repair, or who’s paying for it. But in fact taxpayers are not on the hook yet. Seattle Tunnel Partners (STP) doesn’t officially take ownership of Bertha from Hitachi Zosen until the TBM has made it through about 1,000 feet of Seattle soil with no issues. Even then, says  said Linea Laird, WSDOT’s administrator for the Alaskan Way Viaduct Replacement Program, “More than 90 percent of STP’s work will be performed for a fixed price.”

Meanwhile, cracks in pontoons and mistakes in construction continue to plague WSDOT’s 520 bridge replacement project. In December, WSDOT announced that although specified “hooked” rebar had been left out of three pontoons, they would “structurally adequate” anyway. That omission is, of course, troubling because the rebar in question was supposed to help prevent cracking due to stress.

In an earlier update, in mid-December, titled “Continued progress on SR 520 east approach bridge piers,” WSDOT mentioned that part of that progress was tear-down of a new 58-foot-tall concrete column that had been built with too little concrete over its reinforcing steel skeleton. That was on contracting team Kiewit/General/Manson’s dime.

The state has been pressing for an ambitious finish to replacement of the floating section of the bridge, by late 2014, which presumably was a factor in transportation chief Paula Hammond’s decision not to reject the cracking pontoons shipped so far, proclaiming them mostly cosmetic and of no danger to pontoon integrity. But today Mike Lindblom noted on Twitter: