Substantial savings in crane hire costs was the big benefit achieved on the Kedron Brook crossover structure that is part of Brisbane’s Gateway Freeway upgrade. Crane hire company, BOOM Logistics, was able to introduce to the project a special approach, using its unique equipment.
The crossing, located at a busy part of the freeway, just north of the Brisbane Airport, is being constructed by the Leighton AbiGroup Joint Venture.
The key to the higher productivity and efficiency in this case was the process for moving the big 33m x 75t bridge girders from the trucks, bringing them from a nearby holding bay and positioning them on the headstocks on the piles.
The plan, developed by Stuart Edwards, the Engineer at BOOM Logistics and implemented under the on-site supervision of Lindsay Beutel, was based on using a load sharing beam, enabling two cranes to lift the far end of each girder at furthest reach out over the water ... and BOOM’s unique low profile prime movers.
In particular, it was the ability to combine the low profile prime movers with an alternative lower cost lifting method that was the key.
Explaining the challenge of the site, Stuart said that where the piles were located in the water of Kedron Brook, the earthworks were limited, only being designed to carry the pile driving equipment.
One of the lifting options, in view of the limited earthworks, was a 600 tonne crawler. The crawler needed to be of that capacity to achieve sufficient radius from the bank of the Kedron Brook. It was a costly option.
Another was to call on the Leighton AbiGroup JV to increase the bearing capacity of the earthworks in the waterway ... another costly option.
The next option was to use BOOM’s low profile prime movers to manoeuvre the big girders in closer to their final position and then smaller radius cranes for the final lift.
“We decided the best procedure was to set up the site with three mobile cranes – a 350 tonne Demag, a 300 tonne Liebherr and a 200 tonne Demag, as well as two of our special low profile prime movers.
“Those low profile prime movers, with their one metre high clearance, were the key to it.
“We figured savings overall could have amounted to a few hundred thousand dollars, depending on the add-on costs for one of the options,” explained Stuart.
Outlining the actual lift and shift procedure, Lindsay Buetel summarised the process.
“Firstly, the girders were transported so that one end of the girder was within reach of the 300t and the 350t cranes. This end was then lifted with the load sharing beam between the two cranes. With the loaded low profile prime mover travelling forward and the two cranes slewing with the other end of the girder, we were able to get the girder positioned for the final lift with these cranes,” he explained.
We asked Lindsay how this procedure compared with the time required by an all crane procedure that is without the big advantage of the low profile prime movers.
“The first girder took us 45 minutes and once we got going with the remaining 16 girders it took us about 20-30 minutes for each girder ... that’s from the transport trucks, across the bank to get out to the piles and then lifting into their position,” said Lindsay.
“If a big 600 tonne crawler crane had been used it would have been about 45-60 minutes for each of the 17 girders,” said Lindsay.
BOOM was also able to carry out the works at night, thus not affecting other daylight activities on the site.
“In summary, it was a win for the Leighton-AbiGroup JV in several ways – cost advantage on crane hire, time savings and eliminating the need for additional earthworks.
For the Leighton-AbiGroup JV, lifting techniques introduced by BOOM have represented significant time savings and dollar savings on other sections of the Gateway Freeway project.
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The Kedron Brook crossing on Brisbane’s Gateway Freeway project saw BOOM Logistics introduce considerable savings for head contractor, the Leighton – AbiGroup JV. The technique involved BOOM’s special low profile prime movers which enabled the manoeuvring of the big 33 m girders closer to their final position and thus the use of smaller radius cranes. Another benefit for the head contractor was BOOM carrying out its lift and shift work at night.
The low profile prime mover, with its 1m high clearance, was the key to the savings
On-site Supervisor for BOOM Logistics,
Lindsay
Buetel, pictured above, was able to get the offloading, manoeuvring and lifting of the bridge girders into final position down to about 20 – 30 minutes per girder
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