Locar, Brazil’s largest crane rental firm, has more than 200 cranes, according to Cranes Today Fleet File. The firm is the only Latin American company to own a Liebherr LR 1800, 1,000t lattice boom crawler, and owns other crawlers spanning a range of capacities from 400t to 750t. Amongst its mobile fleet is an LTM 1550 that can lift loads of up to 550t. A fleet of more than 160 hydraulic modular trailers and other specialist transport vehicles complements the company’s range of heavy cranes. The trailers can be used to assemble three drop deck girder bridges, each able to carry 250t, and two straight girder bridges of 450t capacity. It also supplies and uses hydraulic gantries.
The first task was to define centres of gravity for the parts of the plant that were to be removed, and to plan lifting points, spreaders, wire rope and load dimensions. Locar worked with Usiminas Mecânica 24 hours a day to plan these elements of the lift, and to establish a site for the pre-assembly of the new parts.
Locar had to cope with uncomfortable site conditions
Disassembly of the parts of the plant being replaced was carried out in parallel with the production of new equipment. As this was going on, Locar and Usiminas Mecânica’s engineers realised that the LR 1750 would have to be rigged in a series of different configurations to handle the range of loads that needed to be lifted when the new equipment was put in place.
Locar raises powder unit
For the first heavy lift, of a 219t, 56m high, top powder collector block, the LR 1750 was configured with a 77m boom and a 31.5m derrick. The crane carried a back counterweight of 220t, a central counterweight of 95t, and a ballast counterweight of 280t. Locar’s team built a spreader with eight lifting points to attach the block. As the layout of the site restricted luffing of the crane, parts of the plant around the block needed to be moved.
The ‘little church’ closes in
Locar’s LR 1800 mounts the ‘little church’
While one Locar team rigged the LR 1750 to lift the powder collector block, another team prepared the LR 1800 to lift a 111t bleeder platform or what Locar refers to as the ‘little church’. “We had great difficulty in determining the lifting gear, and the lifting points, because it consisted of a complete metallic structure, with platforms, stairways and five bleeder valves that weighed eight tons each,” the company said. The LR 1800 was rigged with a 56m boom, 42m derrick and 77m luffing jib. The central counterweight weighed 32t, the back counterweight 162t and the ballast 440t. The day after set-up, it raised the little church to a radius of 68m and height of 120m in a six-hour lift.
The ‘down comer’ is rigged to hang at an angle
The ‘down comer’ is lifted into place
The final part to be lifted was the down-comer, a tube that takes hot exhaust gases from the blast furnace towards regenerators. While this load has a simple shape – a long cylinder – it needed to be placed diagonally between two curved sections, a placement that demanded fine adjustment. To handle the load at an angle, Locar used a belt with two lifting lugs, offset from the centre of gravity. Two further lifting lugs were used to position the load in the exact angle needed for assembly. Locar used the LR 1750 again for this lift, reconfigured with a 70m boom, 31.5m derrick and 49m luffing jib. The central counterweight was 95t, the back 220t, and the ballast 210t, and the 82t load was lifted to a radius of 44m.
The complete job took 120 days, and more than 1,500 people were involved.
