To assist emergency evacuation of workers during tunnel construction, five 1.5 tonne working load limit (WLL) jib cranes have been installed on the WestConnex underground motorway project in Sydney, Australia. Specified originally for both general lifting and man-riding emergency evacuation, it was after discussions with Australian lifting, rigging and safety specialist supplier Ranger, that a decision was taken to restrict use of the cranes for man-riding and evacuation only.
“WestConnex needed a second point of evacuation from each of the access shafts on the project in the case of an emergency where workers needed to be stretchered out,” said Ashley Thacker, General Manager at Ranger. “If the cranes were also used for goods lifting there was potential for rescue operations to be delayed, which is why it was suggested in consultation to limit their use.”
The cranes feature a 6.5m underslung height with 6m reach and offer heights of lift ranging from 26m to 70m. Ranger chose 3 tonne electric chain hoists from Swiss manufacturer GIS that were downgraded to 1.5 tonne capacity to facilitate man-riding. All were fitted with overload protection, a load cell with read out, pendant and remote controls.
“Given the high profile nature of the site we only sourced from the best manufacturers in each component area. Even then, the hoists needed to be enhanced to comply with Australian standards for man-riding,” said Thacker.
Installation of the cranes was challenging as lifting the columns from horizontal to vertical proved difficult with no dedicated lifting points, and working near open shafts presented potential safety challenges. Upon successful installation, Ranger conducted load testing with water bags and completed training sessions with construction personnel.
The jib cranes will be commissioned by the end of March 2017 and will remain onsite until project completion, scheduled for 2020. Ranger will provide daily operation checks and monthly inspection and maintenance of the units for the duration of the project.
The Westconnex project is a major highways infrastructure project that will construct a predominantly underground motorway system to the west of Sydney to minimise the need for land acquisitions and remove through-traffic from local streets. Tunnels will link the M2, M4 and M5 motorways with other new tunnel systems, providing crucial support for Sydney’s long-term economic and population growth.