Case Studies

Johnson & Young Cranes execute precast beam installation using Mid-Air Transfer

Johnson & Young Cranes (JYC) recently deployed a couple of Liebherr heavy lift cranes to work on Melbourne’s $6.7 billion West Gate Tunnel Project.

The 800t capacity Liebherr LTM1750-9.1 and 400t capacity Liebherr LTM1400-7.1 were implemented to dual lift pre-cast bridge beams, some weighing up to 96T. JYC also deployed its Franna AT40 to assist with the mobilisation and demobilisation. A large crawler crane was unable to be used due to high voltage power lines surrounding the work zone.

The West Gate Tunnel Project is city-shaping and will deliver to Melbourne a vital alternative to the West Gate Bridge, providing quicker and safer journeys, and remove thousands of trucks off residential streets. The project will build twin tunnels under Yarraville between the West Gate Freeway and the Maribyrnong River.

A lot of planning went into these lifts with JYC’s client pouring 15 meter deep piles on the creeks edge for the Liebherr LTM1750-9.1 to sit its outriggers on directly without crane mats. The outriggers of the Liebherr LTM1400-7.1 were placed directly onto the new bridge’s headstock without mats. JYC used the mid-air transfer method for the installation of the precast bridge beams.

A key component to this lift was JYC’s 55t Load Transfer Triangle.

With the Load Transfer Triangle, the LTM1400 is connected to point #1 of the triangle, with point #2 connected to the beam. The 400t crane then leads the end out to the planned point of transfer where riggers are set in an elevated work platform. They then rigged the LTM1750 to point #3 of the triangle. The load is then transferred, freeing up the LTM1400 to take the other end of the bridge beam with both cranes working in unison to set the beam in place.

The beams weight ranged from 81t with the heaviest being 96t. 24 beams were installed in total and six were installed by the mid-air transfer process. The cranes were onsite for just over a week including mobilisation and demobilisation.

The Liebherr LTM1750-9.1 was configured with TY and 204t of counterweight with full outriggers, lifting at a radius of 29m and was operating at 85.7% utilisation and the Liebherr LTM1400-7.1 was configured with main boom and 120t counterweight with full outriggers, lifting at a radius of 17m and operating at 89.3% utilisation.

As a result of the detailed planning and collaboration between JYC and The Client, the lifts were completed on schedule and without a problem.


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