Port of Seattle has broken ground on a new International Arrivals Facility (IAF) at Seattle-Tacoma International Airport, to improve customer experience and respond to local demand for international service.
Skanska, a construction and development company based in Sweden, has announced plans to invest $392M in an office project in Seattle, US.
Construction work has started on Sound Transit’s Northgate light rail station, one of three stations set to open in 2021 with the completion of the Northgate Link Extension.Sound Transit has awarded the $174M contract to Absher Construction Company in August 2016. The scope of the work includes the construction of an elevated station at Northgate, a guideway and a parking garage with 450 stalls for transit users.It will also involve the construction of a transit island, located below the south end of the station platform between Northeast 100th and Northeast 103rd Streets, for convenient light rail and bus connections.According to Sound Transit, trains traveling in the 5.6km twin tunnels north to and from the University of Washington station at Husky Stadium will stop at underground stations in the U District and Roosevelt neighborhoods, exit the tunnels at First Avenue Northeast and Northeast 95th and transition to a 1.3km elevated guideway to reach the new station.Sound Transit CEO Peter Rogoff [speaker in the photo] said: "Within a few years this station will enable many thousands more riders each day to take advantage of fast and reliable travel through some of the most congestion-choked areas of our region."The $1.9bn Northgate Link project extends light rail 6.9km north from the University of Washington to a station next to the King County Northgate Transit Center.
Repairs are finished for giant TBM ‘Bertha’. Patrick Reynolds reports on the two-year-long process.Bertha, better known as Big Bertha, is a 57.5ft (17.53m) diameter tunnel boring machine (TBM) built in 2013 for the Washington State Department of Transportation’s (WSDOT) Alaskan Way Viaduct Replacement tunnel in Seattle, a JV between STP and local firms Frank Coluccio Construction and Mowat Construction, and also HNTB Corp and Intecsa-Inarsa.The machine, built in Japan by Hitachi Zosen Sakai, broke down after an alleged encounter with a steel pipe, damaging several cutting blades, taking two years to fully repair it.By the beginning of 2016, the giant TBM Bertha in Seattle is expected to restart boring on the delayed, central waterfront section of the USD 3.1bn Alaskan Way Viaduct Replacement project, following repairs to the machine.To prepare, Bertha has been undergoing an unusual, if not unique, experience for any TBM, not least the world's largest: she is being buried to commence boring.A 120ft- (36.5m-) deep shaft was constructed to reach the TBM, allowing its vital front section to be brought to the surface for repairs. Following the work, the TBM was reassembled, the cutterhead was turned and other no-load tests were completed. The last task is load testing to relaunch the TBM for its drive below the viaduct.To that end, the shaft has been backfilled with sand and controlled density fill, allowing Bertha to bore once more. Slowly. For a few hundred feet only, at first.Even though the TBM was first launched two-and-a-half years ago, it still has most of its relatively short, 1.7mile- (2.7km-) long tunnel drive yet to finish.The TBM was stopped in a ‘safe haven’, which is a pre-planned, jet-grouted zone designed to allow last checks and adjustments before Bertha bored below the elevated highway again.Fortunately, perhaps, the troubles that brought Bertha to a halt in late 2013 occurred shortly before the machine moved under the seismically-weakened viaduct. Performing a TBM recovery under the viaduct could have been much more difficult. Even outside that zone, the investigation and repairs undertaken presented “a significant challenge”, says Chris Dixon, project manager with Seattle Tunnel Partners (STP), the designbuild JV contractor comprising Dragados and Tutor Perini.Coincidentally, Bertha is preparing to resume boring around the time when, as per the contractor's original schedule target, tunnelling was to have been finished. Bertha is expected to emerge around the beginning of 2017, according to the latest construction schedule issued in November 2015 by STP. The entire Alaskan Way Viaduct Replacement project is to be finished by April 2018.But while the focus shifts from repairing the Hitachi Zosen TBM, and with the tunnelling industry, the coastal city and the state hoping for untroubled progress ahead, the beginnings of legal fights and insurance liability debates over blame have started.The complex arguments over fault, liability and financial consequences are contested between the project owner —Washington State's Department of Transportation (WSDOT), the JV contractor and TBM manufacturer, and various insurers. Lawsuits have been submitted over recent months.Over the two-year standstill, STP and Hitachi Zosen received no payments from the client related to the TBM recovery costs. STP has only received payments for progress achieved on the many other continuing works, such as around the tunnel portals and concreting of the decks within the tunnel bore so far.But, finally, the project looks set to change gear as Bertha prepares to build the rest of the 52ft (15.85m) i.d. tunnel below the waterfront during 2016.Rise of the TBM optionThe aim of the redevelopment project at the waterfront is to improve Seattle's overall transport and economy. Debate over how to do so ran for years, and a host of studies were performed on realizing a fresh infrastructure vision and removing the seismically vulnerable viaduct on state highway SR99.Back in 2008, the leading alternatives did not include the TBM option, especially to construct a large single tunnel, although all possibilities had had reviews.The long-term vision was to create an 'incredible' waterfront for the city — ideally one with minimal traffic on the surface. Putting as much as possible underground was elected to be the way forward, and the deep bore option became a late stage winner in early 2009.The JV contractor proposed building the tunnel with an earth pressure balance TBM, and aimed to have the tunnel open to traffic before the end of 2015. The owner's contract performance deadline was late 2016 for substantial completion of the SR99 tunnel, with performance bonus and penalties either side of the target.STP hired Japan's Hitachi Zosen to manufacture and supply the EPB TBM. Washington state set up an Expert Review Panel (ERP) to look over key assumptions in cost estimates, identify risk during the construction phase, comment on development of funding sources, and consider the project's schedule.Launch, then stopIn late 2011, construction staging commenced in Seattle and manufacturing efforts got underway for the TBM in Japan. The TBM was assembled in dry dock in late 2012, before it was shipped across the Pacific Ocean to Seattle.Many activities in both Seattle and Japan were on the critical path of the project schedule, the ERP cautioned in its February 2013 report. It issued an opinion that the target launch date of June 2013 was not expected to be achieved.However, the TBM was assembled in Seattle over April-July at the south end of the tunnel alignment, and then formally launched at the end of July 2013.Bertha's 2-mile- (3.2km-) long drive was expected to take about 14 months. In its following report of February 2014, the ERP noted that early operation of the TBM had delivered better than expected performance.The tunnelling plan was to set off slowly. The TBM would stop early to perform planned maintenance and checks at key ‘safe havens’ along the first 1,500ft (457m) of the northward drive before then diving below the elevated highway.By early December, and despite the late start in mid-year, the shield had advanced more than 1,000ft (305m), reaching where it was expected to be against the schedule, the ERP reported. The panel also said the shield had advance more quickly than expected by the project team, and pulled back time against the schedule. But then trouble struck. The machine overheated and progress slowed as “unanticipated and increasing resistance was experienced”, WSDOT reported. The TBM was stopped on December 6, 2013.At that point, as per the contract between STP and Hitachi Zosen, STP was about to take ownership of Bertha from the TBM manufacturer. Hand-off was planned to follow after the first, proving and settling, stage of tunnelling, constructing the tunnel up to Ring No. 200, as WSDOT had noted in a statement on December 5, and Dixon confirms.Investigation and recovery planWith Bertha stopped under cover of 60ft (18.2m), the contractor lowered the high water table around the TBM. Drilling wells to a depth of approximately 120ft (36.5m), water pressure was reduced to enable the TBM crew to safely start inspecting the machine’s excavation chamber in early January 2014. Probe holes were also bored ahead to check for potential obstructions.The investigation of the top 15ft (4.6m) of the chamber revealed a piece of 8in (200mm) diameter pipe — a section of steel well casing — in a cutterhead opening, WSDOT reported at the time.In late January, a programme of hyperbaric interventions allowed inspections into more of the excavation chamber. Many of the cutterhead openings were found to be clogged, which was then viewed as the more likely cause on the mining difficulty and not major obstructions — none of which were found inside or in front of the TBM, WSDOT said in February 2014.Then, as a trial, STP restarted the TBM to build a ring. More high temperatures were recorded, like before the December stoppage. Investigating further, STP found damage to the main bearing seal.Laura Newborn, spokeswoman for WSDOT, has expanded on the initial information, explaining to Tunnels & Tunnelling North America that the well-casing was found inside the material blocking a cutterhead opening."The cutterhead was clogged," she says. "The piece of metal was not blocking the opening."She adds that the metal detected in front of the cutterhead turned out to be the nose of the cutterhead. "There was no metal found in front of the machine," she adds.WSDOT said at the time that the steel pipe found in the cutterhead was a well casing, installed in 2002 and used by geologists to study groundwater flows following the 2001 Nisqually earthquake. The owner added that location of the pipe was included in reference materials in the contract. However, according to JV contractor member Tutor Perini's third quarter-2015 results, presented in its 10-Q filing to the Securities and Exchange Commission, STP claims the steel pipe to be a "differing site condition that WSDOT failed to properly disclose." Tutor Perini added that the Disputes Review Board had said the pipe was a differing site condition, but noted that WSDOT has not accepted the finding. WSDOT's spokeswoman told Tunnels & Tunnelling North America the "root cause of the damage to the TBM is still under investigation."Reach and repairSignificant repairs would be needed at the TBM. The ERP said the stoppage to TBM tunnelling would throw out the project schedule by some months. It called on the client and contractor to stay away from debates over blame and financial liability, and keep their focus on investigating and resolving the technical problems.In its February 2014 report, the panel advised that the contractor be given appropriate time to develop a recovery plan. "Returning the TBM to operation should be everyone's primary objective," it added.During the halt in work, the contractor undertook wider inspections and also maintenance work, including replacing damaged cutter tools. But the discovery of damage to the bearing seal system also called for replacement of the main bearing. With such major works required, it was decided that the TBM could not be repaired underground. The shield had to be accessed from the surface and opened up to retrieve the cutterhead and cutter drive unit. STP developed a recovery and improvement plan, which it believed would allow the repaired TBM to resume tunnelling in March 2015.STP's plan was to sink a large diameter access shaft a little ahead of the halted TBM. The 80ft- (24.3m-) wide shaft was built through much of 2014 and readied to receive the TBM.The dormant machine was restarted in February 2015. It broke into the shaft and came to a rest on a concrete cradle, cast on the base of the shaft. Hitachi Zosen hired a heavy lift contractor to extract the front sections of the TBM, and this was done in late March. Mammoet designed a modular lift tower capable of sliding over the 120ft-deep shaft and repair area.Soon after, in its April 2015 report, the ERP said that while reasons for the TBM problems were not yet clear, and also were subject to ongoing legal and commercial debates, the contractor had been constructively using the stoppage period, adding that STP planned "to apply some lessons learned" from the tunnelling work done up until then. The ERP, through its discussion with project parties, said in its April 2015 report that the recovery plan for the TBM "appears to be viable," adding it was reasonably confident the machine could be repaired.The panel added that STP and WSDOT had shared information — "without direction from WSDOT" — on how to improve the TBM's function. "It appears that many of WSDOT's comments have been considered in the redesign and repair plan," ERP said.WSDOT had formed its own Restart Team to monitor the contractor's work and risk and mitigation efforts. "Fully disassembling and assessing the machine was always the key to determining how long the repairs would take," said Dixon, in mid-2015.Revise and rescheduleThe ERP commented the stoppage was "unusually long" due to the scale of investigation and repairs needed, and the area was a congested urban environment with geotechnical challenges. Working around the core recovery challenge, the contractor examined and re-programmed a number of other tasks for the tunnel, such as manufacturing all of the precast segments needed for the entire tunnel and storing them, ready for use. Other re-programmed construction activities, helping to offset some of the effects of the TBM stoppage, have included, says Dixon: • Completing the underground structure of the south operations building; • Constructing the interior cast in-place concrete roadway structure within the completed portion of the bored tunnel; • Advancing north and south cut-and-cover sections enough for their handover to other works packages; and, • Redesigning M&E systems, installing and commissioning them faster in sections instead of keeping with the original plan of doing everything in one go after excavation is completed. By the time of ERP's report in April 2015, the panel had learned the contractor then expected a later restart of the TBM — in August.It also noted, and as STP and WSDOT have continued to say, the rescheduled completion target cannot be determined until after the TBM has been restarted, has bored again but also has been re-checked at the last safe haven.In mid-July, installation of the new main bearing commenced. But the schedule was pushed back further with TBM restart then pencilled for late November.Hitachi Zosen completed the above ground repair works in mid-August, allowing the heavy sections to be placed back down the shaft for reassembly at the open front end of the TBM. Finally, in late November, the cutterhead was rotated and system checks performed in a "no load" test.With those successes, the access shaft finally could be backfilled. The next crucial step for Bertha are the pitstop checks. All being well, the big bore will proceed below Seattle's waterfront over the coming months.* This is a version of an article that first appeared in Tunnels & Tunnelling.
The regional transit authority serving the Greater Seattle Area Sound Transit has inaugurated the University Link Light Rail Extension in Seattle.CH2M, serving as the lead in a construction management joint venture, announced that the rail project has been delivered six months ahead of schedule and about $200M under its $1.6bn budget.The 2.5km extension runs through twin-bored tunnels from downtown Seattle north to the University of Washington, with stations at Capitol Hill and on the university’s campus near Husky Stadium.The project involved nine separate contracts for the demolition, utilities, site preparations, two underground stations, 2.5km of twin-bore tunnel with precast placed liner, 21 hand-mined cross passages and expansion of the pre-existing rail yard. CH2M provided overall programme management, resident engineering, inspection, project controls, cost estimating, constructability reviews and contract administration for the project that lasted eight years.The project is estimated to nearly double weekday ridership on the existing light rail line to more than 70,000 riders by 2020.
Sound Transit has broken ground on the $3.7bn East Link light rail extension project that will connect Seattle, Mercer Island, Bellevue and Redmond's Overlake area and Microsoft campus.The 14-mile light rail will provide 24-minute trips from Bellevue to Westlake Station in downtown Seattle.Contractors have started site preparation just south of downtown Bellevue near East Main Street and Northeast 112th Street, where a tunnel portal will allow trains to transition from the surface to a 1/3-mile-long tunnel before re-emerging at the surface near Northeast Sixth Street.East Link's 10 stations are expected to open in 2023. By 2030, East Link is likely to carry about 50,000 people daily.