By Shani Wallis, February 12, 2015
As excavation of the recovery shaft for the Alaskan Way TBM
repair in Seattle reached invert level, technical expertise to oversee
the complex repair process has been appointed by the TBM’s manufacturer.
TunnelTalk has learned that Gomez International of Arizona has
been retained by Hitachi to manage the process to remove, lift out,
repair, lower and refit the cutterhead and main bearing drive unit of
the 17.5m diameter EPBM.
The Gomez team of specialist mechanical, electrical and
logistics engineers will manage the activities of the subcontractors and
crews engaged by Hitachi to complete its contractual commitment to
repair the TBM to its designed and delivered working condition.
The Gomez International team manager has been on site in Seattle since December 2014 and with his team will direct subcontractors including crane operator Mammoet Company of The Netherlands which has installed one of the world’s largest tower cranes over the recovery shaft to lift and maneuver the world-record 17.5m diameter cutterhead and its main bearing drive unit; and specialists National Welding which will undertake up to as much as 150 tonne of welding required by the repair process. The repair process also includes a team of about 25 engineers from Hitachi assigned to Seattle, and the crews of engineers and laborers made available to the process by the project’s design-built contractor Seattle Tunnel Partners (STP), Dragados and Tutor Perini.
Gomez International knows well the TBM and its systems. It was engaged by Hitachi as its US machine and systems consultant during the procurement, design and manufacture of the mega machine and to represent Hitachi as part of its team in strategic meetings with the Spanish/US client STP and the project owner WSDOT and their consultants and advisors. Its engagement with Hitachi was to proceed through the TBM assembly and commissioning stages but the company was released from its contract when STP took delivery of the machine at the port of Seattle.
The Gomez International team manager has been on site in Seattle since December 2014 and with his team will direct subcontractors including crane operator Mammoet Company of The Netherlands which has installed one of the world’s largest tower cranes over the recovery shaft to lift and maneuver the world-record 17.5m diameter cutterhead and its main bearing drive unit; and specialists National Welding which will undertake up to as much as 150 tonne of welding required by the repair process. The repair process also includes a team of about 25 engineers from Hitachi assigned to Seattle, and the crews of engineers and laborers made available to the process by the project’s design-built contractor Seattle Tunnel Partners (STP), Dragados and Tutor Perini.
Gomez International knows well the TBM and its systems. It was engaged by Hitachi as its US machine and systems consultant during the procurement, design and manufacture of the mega machine and to represent Hitachi as part of its team in strategic meetings with the Spanish/US client STP and the project owner WSDOT and their consultants and advisors. Its engagement with Hitachi was to proceed through the TBM assembly and commissioning stages but the company was released from its contract when STP took delivery of the machine at the port of Seattle.
Repair strategy for the giant TBM explained:
https://www.youtube.com/watch?v=QlPgkPo_vGQ
As mechanical repair teams mobilize, WSDOT confirmed completion this week of the 24m diameter x 36m deep (80ft x 120ft deep) recovery shaft with installation of nearly 800m3 (1,000yd3) of rebar reinforced concrete to form the base slab and cradle on which the 17.5m (58ft) diameter EPBM will rest for its process of refurbishment and repair. Work will continue to prepare the seal and tunnel eye through which the TBM will emerge. Over the past 13 months since the TBM came to a stop in December 2013, maintenance crews have kept all its systems in operating order to ensure prompt start up and breakthrough into the recovery shaft. If the machine is unable to bore through the 6m (20ft) thick diaphragm wall of the shaft, a connection will be made from the tunnel eye in the shaft.
https://www.youtube.com/watch?v=QlPgkPo_vGQ
As mechanical repair teams mobilize, WSDOT confirmed completion this week of the 24m diameter x 36m deep (80ft x 120ft deep) recovery shaft with installation of nearly 800m3 (1,000yd3) of rebar reinforced concrete to form the base slab and cradle on which the 17.5m (58ft) diameter EPBM will rest for its process of refurbishment and repair. Work will continue to prepare the seal and tunnel eye through which the TBM will emerge. Over the past 13 months since the TBM came to a stop in December 2013, maintenance crews have kept all its systems in operating order to ensure prompt start up and breakthrough into the recovery shaft. If the machine is unable to bore through the 6m (20ft) thick diaphragm wall of the shaft, a connection will be made from the tunnel eye in the shaft.
Testing of TBM Bertha at the Hitachi factory in Japan in December 2012:
https://www.youtube.com/watch?v=EMIorr7DJ7c
For about 25 years, the company has worked as a mechanical consultant for the US division of Japanese contractor Obayashi and was involved in its many hard rock TBM CSO tunnel drives in Atlanta; as well as the Eglinton Subway tunnel project in Toronto, Canada, and on construction by Obayashi of the high level Colorado River bridge to bypass the road that crosses on the crest of the iconic Hoover Dam.
A senior engineer with Gomez International, Asao Nomura, worked on the mega TBMs of more than 14m diameter used in the 1990s to excavate the Trans-Tokyo Bay highway tunnel in Japan, and who came to the United States more than 15 years ago to work for Obayashi on its first tunneling contract in North America for the CSO drainage program in Atlanta. Nomura, for Gomez International, was involved in its advisory role with Hitachi during the design, manufacture and procurement of the SR99 machine. Gomez and Nomura were interviewed by TunnelTalk during the visit to the Hitachi factory in Sakai, Japan for initial inspection and dedication of the machine by STP and WSDOT in December 2012.
Gomez (right) and Nomura speak of TBM procurement involvement:
https://www.youtube.com/watch?v=tmrS4nrCaBM
For its part Hitachi has remained committed to the mega EPB machine in Seattle from the start of its operating troubles. Without knowing the root causes of the TBM breakdown - whether they be mechanical or operational - Hitachi has played a proactive role in recovering the situation. Since replacement of the main bearing was considered a prudent risk management strategy after failure of the main bearing seals, Hitachi has advanced its part of the process without delay. All replacement parts and components for the repair are on site and are being made ready for the process, and all the mechanical costs involved with repair of the TBM are being covered in this initial instance by Hitachi.
https://www.youtube.com/watch?v=tmrS4nrCaBM
For its part Hitachi has remained committed to the mega EPB machine in Seattle from the start of its operating troubles. Without knowing the root causes of the TBM breakdown - whether they be mechanical or operational - Hitachi has played a proactive role in recovering the situation. Since replacement of the main bearing was considered a prudent risk management strategy after failure of the main bearing seals, Hitachi has advanced its part of the process without delay. All replacement parts and components for the repair are on site and are being made ready for the process, and all the mechanical costs involved with repair of the TBM are being covered in this initial instance by Hitachi.
The SR99 TBM is not the first machine in the world to experience serious problems and it will not be the last. All similar incidents in the past have been repaired, recovered and restarted to complete the project successfully. The same is possible and planned for the mega machine on the SR99 project in Seattle.
References
- TBM Bertha repair strategy, Video – TunnelCast, April 2014
- Alaskan Way contract awarded to Seattle Tunnel Partners – TunnelTalk, January 2011
- Mega EPBM for Seattle tested in Japan, Video – TunnelCast, December 2012
- Seattle Northgate Link TBM dedication Video – TunnelCast, DApril 2014
- Seattle U-Link prepares to receive its TBMs – TunnelTalk, March 2011
- San Francisco Bay Tunnel breakthrough, Video – TunnelCast, January 2013
- Beacon Hill celebration and investigation – TunnelTalk, July 2009
- Double breakthrough for Eglinton Crosstown west TBMs – TunnelTalk, January 2015
- Tracking mega TBMs – TunnelTalk, Discussion Forum