In September 2002, in First sight, we reported on the development of the so-called Athey crane by Balfour Beatty Power Networks, a division of the international contractor Balfour Beatty. At the time of our first report it had been tested in the yard in the UK where Balfour Beatty had put it together, but that was about it. Since that time it has been shipped from the UK to South America and put to work by the customer that ordered it, Transener, the company that is responsible for maintaining power lines throughout Argentina.
As previously reported, this crane – effectively ‘home made’ – uses Akerman excavator tracks and 45m of NCK Andes lattice boom in 3m sections. It lifts 10t at a 9m radius and hoisting power comes from a 70kW Cummins engine.
Transener wanted the crane to be as simple as possible. Additional features such as powered tracks and automatic self-levelling were offered but rejected.
For transport to Argentina the base machine was stripped of its jib base section, forward mast, derricking rope and counterweight. Hydraulic oil and fuel tanks were drained. The base machine was shipped on a standard 40ft flat rack and the rest of the equipment went into two 40ft curtain top containers. Shipment was made to Santa Fe after clearance from port at Buenos Aires.
Transener needs the crane to restore power lines and pylons that have been blown down by storms. Its goal is to get power restored as quickly as possible and it has to work in some remarkably remote areas, on difficult ground in pampas areas. To speed erection, Argentinian pylons are erected on the ground with a cross section at the top and two legs. As the structure is hoisted up, the feet of the two legs are brought together so that the whole pylon effectively stands on one foot. It is then supported in place by four guy ropes. This design not only considerably reduces the wind loading on the structure, it also reduces erection time. The four legged pylon style used in the UK and elsewhere can take more than a day to erect. Transener can hoist these up in just 30 minutes.
The photos on these pages show Transener testing the crane on the largest size of transmission pylon that is has to erect. The load weighs just over 8t, excluding the spreader, and the pylon – once erect – stands about 40m high.
Balfour Beatty’s Rob Sonnex, who managed the design and construction of the Athey crane, says that there were no real problems during the commissioning or testing of the crane. ‘The three crews on site for instruction were more than competent to operate the crane systems with minimal guidance, and they all worked extremely well as a team,’ he says.
Transener initially wanted to use an old International bulldozer that it already had, but the towage was not suitable, as it was rigid rather than rotating. So instead a low ground pressure Caterpillar D6 dozer was dispatched to Santa Fe from Henderson some 800km away, which meant a couple of days lost work for the testing crew.
Once the Cat dozer arrived, the crane proved itself and the tests went smoothly. There were still a couple of things for Sonnex to remain nervous about, however. ‘The only other slight problem was the location of the test, within a live high tension sub station,’ he says. ‘And during the week of the test in Santa Fe we also encountered poisonous snakes and freshwater alligators.’
