How do you transport an awkward quasi-trapezoidal shaped girder that's over 21 m long, 6.3 m wide, 6.5 m high and weighs over 83 tonnes while abiding by Queensland road restrictions? Well with great difficulty unless you think outside the box.
The transportation of over-dimensional loads via road do not usually present huge challenges for logistics companies. Normally large indivisible loads are designed with transportation regulations in mind. The design process should take into consideration road restrictions including weight, length, height, width restrictions and expected obstacles along the transportation route.
However in this case, when the Main Girder 1 was designed, the Chinese manufacturer did not taken into account considerations for Queensland road restrictions. After the girder was manufactured the client and the Original Equipment Manufacturer conducted several studies to reduce the overall height but no suitable solution could be reached. Cutting the girder up to move it and then weld it back together was dismissed as it was too expensive and the risk of damaging the internal stiffening was considered too great.
What needed to be considered?
The maximum height allowable along the route was 6.6 m without the need to remove existing electrical aerial wires. Our load was 6.5 m which meant the load had to be transported no greater than 10 cm from the road. Isolation, removal and reinstatement of overhead electrical wires is prohibitively expensive not to mention the provision of alternative power so as not to disrupt the community.
Due to the height of the girder it couldn't just be placed on a trailer and taken to site as there were no commercially available trailers that were 10cm off the ground.
When formulating options TEAM came up with the winning plan. The girder would be rolled 180 degrees along its axis and suspended between the decks of two trailers to achieve a maximum combined travel height of 6.6m. To achieve this TEAM designed a support for the rear end which in turn was supported on a remotely controlled steerable heavy duty bogey set.
This solution met the requirements and was approved by the National Heavy Vehicle Regulator.
What were the challenges?
To make our plan work we needed to roll the Girder. The whole 83 tonnes. To make it more challenging the Girder had not been designed with lifting lugs for rotation. We needed to ensure the concentrated lifting loads did not permanently distort the thin walled girder.
But that did not stop us! 7 months of planning and preparation the girder was shipped to site on schedule. Want to find out more about this project?
Read about the Grosvenor Mine Project