Tutt Bryant Heavy Lift and East Coast Cranes recently removed a dry dock gate weighing more than 300 tonnes at a historic World War II – era dry dock on behalf of Cairncross Dockyard in Brisbane.
The dry dock gate, measuring 37 metres in width and 14 metres in height (with 10 metres submerged), has a rich history. Cairncross Dry Dock, the second largest in Australia, was constructed for wartime ship repair. Post-war, it continued operations as a major hub for ship repair, accommodating Panamax-class vessels and as a base for heavy infrastructure projects.
The gate was not designed to be lifted and had no original lifting points or precise weight specifications, making planning of the lift an engineering feat. Adding to the challenge, the gate held approximately 180 tonnes of water as ballast and was located beneath Brisbane Airport’s flight path. Scott De La Rue, Tutt Bryant’s Heavy Lift and Shift, Projects & Heavy Lifting Manager East Coast discusses the project.
“For this job our client was East Coast Cranes and the land owner and the dock owner were East Coast Cranes’ customer. We were initially contracted to lift a pontoon into the water, it was one of the little riverside stations used to catch ferries. This weighed 180 tonnes. Then, at relatively short notice, the customer decided that while the large capacity cranes were onsite and given the cost of getting them there, it provided an ideal opportunity to lift the dock gate. They hadn’t done anything with this for many years and in the end we had approximately two weeks to plan the dock gate element of the lifts,” said Scott.
Tutt Bryant Heavy Lift and Shift deployed its Sany SCC4500A 450t capacity lattice crawler crane for the lifts.
This lattice boom crawler is powered by a Cummins diesel engine with rated power of 298kW/1800rpm and maximum torque of 1898N.m/1400rpm. SYIC-I integrated control system – power, engine, main control, LMI, auxiliary and safety monitoring systems. The operating weight is about 380t including the upperworks, lowerworks, rear counterweight of basic machine, carbody counterweight, 24m basic boom and 450t hook.
The SCC4500A lattice crawler crane is built with enhanced safety features including load moment limiter, over-hoist protection of the main and auxiliary hooks, over-release protection device of the main and auxiliary hook, brake of hoisting mechanism, CCTV monitoring system, fault auto-diagnosis system, anemometer and many more.
The Sany SCC4500A was in HDB/Super Lift configuration with 66 metres of main boom and lifting at a radius of 17 metres.
Scott goes on to discuss the site and the complexities of the lift.
“We were operating on one of the best sites I’ve seen in years. There was plenty of room to mobilise and demobilise the Sany and it only took us two and a half days to build it. The support crane was East Coast Cranes’ GROVE GMK7450, 450t capacity all terrain.
“Basically, there were four stages to this project. The first was lifting and placing of the pontoon into the water, the second was the lifting of the dock gate out of the water and the third was landing the dock gate and re-arranging the rigging, and the fourth was laying the dock gate over on its side. The GROVE was also the support crane when we laid the dock gate over.
“What made the performance of the Sany all the more impressive was that when we started to lift the dock gate we expected it weighed around 500t with 270t of water inside it. We got as much water out of it as we could and then lifted it as far as we could, while still being capacity. We didn’t get it all the way out of the water, but it gave us an opportunity to put holes on the side of the dock gate to release more water.
“We were expecting the lift to come in at about 230t but it didn’t. Even when we got all the water out of it, it still came in at 308t. That was dead weight and didn’t include anything else like the rigging,” said Scott.
The lift required a complex rigging configuration, which included a Modulift MOD 400 and two MOD 250 spreader beams in a one-over-two rig configuration.
In such high-stakes projects, Modulift’s versatile spreader beams demonstrate their engineering excellence. The MOD 400 was deployed at a 16-metre span, while the two MOD 250 beams operated at 4-metre spans each.
Together, they distributed the load evenly, ensuring optimal stability and safety throughout the lift.
“We had a series of slings basketing under the dock gate and once we had it out of the water, and onto land, we connected East Coast Cranes’ 450t Grove to the top of the load taking over 100t of weight to stabilise the gate vertically,” Scott said.
“We then de-rigged the basketing slings, and then re-rigged with two, 150t equalising sheeves and a series of 100 grade 32mm chains to lay it over.
“At this stage there was a load moment where the gate shifts from vertical to starting to lay over, and there’s a shock load that we needed to eliminate. This shock load would have been above the capacity for the rigging gear that we had on the load.
“The Grove ensured there was no shock load in the load moment as it shifted perfectly through 90 degrees into rolling over.”