Rough terrain cranes are invaluable jobsite tools and used in a variety of applications from refineries and petro-chemical facilities to general construction sites. And while many of these sites are open and easy to access, working in confined lifting conditions can be much more challenging.
This is precisely why the design and variable steering modes of the rough terrain crane were created: to enter and work in confined lifting spaces. During the construction of the Freedom Tower, Bay Crane was required to perform crane work in one confined corner of the project.
To accommodate for this work area, one outrigger had to be deployed at less than full extension. Even though any rough terrain crane may be able to safely lift at full capacity over outriggers that are fully extended, most cranes would be required to reduce the load chart to the capacity of the shortest outrigger extension. Given the requirements of the lift, this would have made the crane inadequate to perform the required lifts.
Enter Asymmetrical Outriggers
In this case Bay Crane was using a Tadano GR 150XL-2 rough terrain crane, so they were able to take advantage of Tadano’s exclusive asymmetrical outrigger feature. The crane uses its AML-C load limiter to realize, monitor, and provide lifting capacities for an infinite amount of asymmetric outrigger configurations.
Tadano pioneered this crane feature some ten years ago. See the Leap Awards from 2005 for more on how Bay Crane has been using it to their benefit. The AML-C automatically detects the outrigger configuration and calculates the maximum lifting capacities through each available working range.
When swinging from the more stable to less stable outrigger areas, the AML-C automatically detects the configuration according to each of the outrigger extended widths, and brings the swing motion to a slow stop before it reaches the limits of the allowed capacity. Therefore, even if the operator attempts to perform the crane operation without being aware of a change in the capacity, the AML-C will prohibit the crane from working outside the permitted chart to ensure a safe crane operation.
Evaluating Rough-Terrain Crane Options
Regardless of the size and application, at some point most all rough terrain cranes will find themselves being required to enter and work in confined lifting areas. And more often than not those areas will prohibit the ability to fully deploy all 4 outriggers. The asymmetrical outrigger feature on the Tadano rough terrain cranes provide a convenient and reliable system for working safely and getting the job done in confined lifting areas.
For a comparison of load charts under different conditions, sign up for a free load chart assessment consultation today!