The 98t, 17m-long, 2.4m-wide tunnel boring machine features seven sections weighing between 4.9t and 27t. The seven sections of the machine had to be lifted independently so to avoid any load being placed upon the joins, which would have damaged seals and allowed water to penetrate.
To satisfy this requirement, Kennards supplied a modular spreader beam, the largest ever manufactured in Australia. It can be varied in length up to 20m, can lift loads up to 145t at 13.5m, while at 20m it can carry 76t.
Nobles, which devised and co-supervised the lift, used the beam at a 10m length with 6m, 2m, and 1m sections plus end sections.
“Originally, we intended creating our own beam, but we were delighted when we found out this one was available because we had only about five weeks to put the job together,” said Gary Stewart, from Nobles’ big lifts division.
“We understand from Herrenknecht AG, the manufacturer [of the tunnel borer], that it may be the first time a tunnel borer has been lifted from under the water.”
Melrose employed a Grove GMK7450 all terrain crane for the lift operation.
The lift also faced issues with wind and swell in Botany Bay, with the initial window for the lift, which offered favourable conditions, postponed by two days. This meant work to lift the borer commenced with a rising tide and wind speeds of five knots rising to 10 knots.
“The tunnel borer would…be gradually lifted to the surface, with the load cells closely monitored to ensure no section took more weight than designed,” said Stewart.
“If a section came close to the design load, the [machine] would be lowered, the rigging screw adjusted and the lift process repeated. The adjustment process in achieving correct loading was time consuming, and with the rising tide and winds reaching up to 10 knots, stress was abundant.
“But it was all smiles when the [machine] was removed from the water and deposited on land.”
