March 4, 2015
Bertha has moved forward a total of 57ft since resuming her short
drive on February 17. In that period the 17.5m diameter machine has
completed nine permanent concrete tunnel rings.
With Bertha now in position, crews have begun the challenging task of disassembling the world’s largest tunneling machine. They will move through a number of methodical steps as they prepare to lift four pieces weighing up to 2,000 tonne to the surface for repairs.
According to WSDOT completion of the repair – which involves replacement of the damaged bearing seals and the fitting of a brand new new main bearing as a precautionary measure – will take “weeks”.
With Bertha now in position, crews have begun the challenging task of disassembling the world’s largest tunneling machine. They will move through a number of methodical steps as they prepare to lift four pieces weighing up to 2,000 tonne to the surface for repairs.
According to WSDOT completion of the repair – which involves replacement of the damaged bearing seals and the fitting of a brand new new main bearing as a precautionary measure – will take “weeks”.
References
- Bertha recovery shaft breakthrough – TunnelTalk, February 2015
- Technical management of TBM Bertha repair – TunnelTalk, February 2015
- Seattle TBM recovery shaft repair row – TunnelTalk, January 2015
- Discussing Seattle TBM repair strategy – TunnelTalk, February 2014