The compact power of the Liebherr LR 1160 crawler crane is currently being clearly demonstrated on a power plant in southwest Indiana in the USA.
Crane access is restricted to a narrow roadway just outside the plant's perimeter wall. Trees along the side of the road restrict slewing space at the rear. Tail swing is limited to 90 degrees to avoid counterweights hitting the building. Ground bearing pressure is also a cause for concern because the road is built on an embankment alongside a river below.
Having to set up a crane so close to the wall means that the main boom has to be raised close to vertical and a luffing jib attached to make the picks.
Crane rental specialist AmQuip specified a Liebherr LR 1160, which was just compact enough to squeeze down the road and slew in the limited space available. To keep down its weight - and thus meet the restrictions on ground bearing pressure - AmQuip's crew reduced the upper counterweight from 121,300 lbs (55.1 tonnes) down to 99,000 lbs (50 tonnes). The 33100 lbs (15 tonne) central carbody ballast was also removed.
With the center pin of the crane just 15 ft (4.6 metres) from the building, the main boom has to be angled at a near-vertical 88 degrees to make lifts of up to 13,000 lbs (six tonnes) at a radius of 135 ft (41 metres).
Jim Creek, vice president of AmQuip's Power Division, reports: "This is a unique job. We needed a crane that was compact enough to maneuver in the limited space available, with extra low ground bearing pressure, but could still make all the required lifts.
"Even with reduced weights, the LR 1160 maintained a very good chart, and it was easy to erect and fit into the space provided."
The Liebherr LR 1160 is made in Austria by Liebherr-Werk Nenzing, which is represented in the Americas by full sales and service subsidiary Liebherr Nenzing Crane Company.
Scott Moreland, vice president of Liebherr Nenzing Crane Co., explains the advantages offered by Liebherr cranes on jobs like this.
"Other crane manufacturers offer up to maybe three different reduced counterweight configurations. Liebherr offers seven. And while other crane manufacturers supply load charts showing a limited number of angles for the main boom when fitted with luffing jib, a Liebherr crane can lift a load off the luffing jib with the main boom at any angle you need, from 45 to 88 degrees and any degree in between. It can even boom and luff simultaneously, even under load. That's the beauty of Liebherr's Litronic control system - it actually calculates the load chart in real time."