Borger Cranes and Rigging recently completed a double tank lift at the Brisbane Convention Centre. The lifts were complicated due to the weight limits of convention centre’s concrete slab.
Borger Cranes Supervisor, Owen Ainsworth explains more.
“The lifts were complicated because we had to factor in the weight baring issues relating the convention centres’ concrete slab. We delivered and unloaded the tank for a trade event and collected it a few days later.
“Each lift was approximately 40t which included the hook and rigging. We deployed our Grove GMK6300 with 50t of counterweight. The choice of this crane was based not only on capacity, but also the spread of the outriggers which worked best with the column spacing under the slab,” he said.
“The crane performed perfectly. We lifted the tank at 14m which meant the crane was performing at 87% of its charts. There were height restrictions on the second lift, and we had to use cumalongs to position the counterweights as we could not jib the boom high enough for the crane to place them,” said Ainsworth.
With concerns about the concrete slab and ground pressure restrictions vehicle access and the lifts themselves were carefully planned says Ainsworth.
“All vehicle details were sent to the engineers for sign off before entering the hall. All expansion joints were backed propped and once the crane was placed over the propping and set up, only one loaded truck was allowed on the same section at a time. Counterweights were split into single trailer loads.
“We set the crane up initially in each position without counterweight then took the load back off and prestressed all props right through to basement. A surveyor and engineer were on site the whole time monitoring any movement in the slab. No pads were used during the lifts, we ended up using 1.2m x 1.2m timbers to match the propping underneath the slab,” he said.
“50t capacity custom made slings were provided by client which made life a little easier. It is lifts like these that make the job so worthwhile. We know they wouldn’t be possible without all parties working closely together ensuring every detail is covered and the lift is competed safely and without incident,” said Ainsworth.