When Australian firm McMahon Services carried out a number of complex demolition projects at the Adelaide Convention Centre, it used a Rammer 777 breaker fitted to a significantly modified excavator for this challenging task.
Part of an upgrade and modernisation programme, the most recent work involved the deconstruction of the Convention Centre’s Plenary Building. Built almost 30 years ago, this is to be replaced with a multi-purpose 3,500 seat facility, scheduled for completion next year.
The Rammer 777, fitted to a modified Komatsu PC138-8 excavator, was used in the demolition of the Plenary Building’s four circular stair structures, each 8 metres (26 ft) in diameter and 13 m (42 ft) high, as well as to demolish concrete walls up to 250 mm (10 in) thick.
To reach the stair structures, the excavator was fitted with a 16 m (52 ft) long-reach boom.
This required the use of a smaller than usual breaker for this size of carrier so it did not exceed safe working loads.
In addition, because the work required the excavator to work on a suspended concrete slab – which also had to be demolished in the course of the project – it was heavily modified with an extended undercarriage system to better spread the weight over the floor area.
“It was important that we had the right weight, power and capacity in the breaker to remove the concrete stairwells and slabs efficiently,” said Ryan Brown, national business development and brand manager at McMahon.
“We worked closely with Renex, the Rammer dealer in South Australia, to make sure we achieved the best outcomes, fitting in with our existing equipment and helping us develop new solutions. It’s not just about picking up something off the shelf, but making sure that the product comes together and works seamlessly with our other equipment,” he added.
Daniel Drew, Renex’s Rammer specialist, said the company worked with Komatsu and McMahon to match the breaker properly to the PC138-8. This was essential given the extensive modifications to the excavator which meant that its safe working capabilities had changed.
“The most critical factor was matching the weight of hammer to the modified excavator, giving close consideration to the length of boom, length of tracks and width of the track frame to ensure the machine didn’t tip at full reach over the side of the tracks,” said Daniel.
“It had to be able to operate safely in a ‘pick-and-carry’ out the side, which meant the breaker weight was not to exceed 500 kg (1,102 lb)
“At 385 kg (849 lb), the Rammer 777 was well within that weight limit.
“In addition, the PC138-8 is able to have the flows controlled through the ECM as the auxiliary is electronic. Once set, a flow meter is connected to the excavator’s auxiliary circuit to ensure accurate delivery of no more than the breaker’s requirement of 120 l/min of oil at 140 bar pressure.”