It’s actually seldom that a bridge crane can be laid out in a perfectly rectangular way. Usually, there are obstructions and accessibility problems that get in the way. One of the most routine problems is forklift accessibility. One side of the crane has to be kept clear for forklifts and for racks.
That’s where the cantilevered bridge crane is useful.
What is a Cantilevered Bridge Crane?
What is a cantilevered bridge crane? A bridge crane is a crane that consists of a bridge rail that travels along 2 runways. A cantilevered crane means that the crane is projected beyond, or overhung beyond, a set of columns.
In the above photo, the whole crane is cantilevered from just 2 columns, where the columns are screwed to the floor via large baseplates. The crane rail in this case is C250 G-Rail™.
How do Cantilevered Bridge Cranes Work?
This type of bridge crane can support a large load from a very small footprint. To allow the floor to withstand the overhung load, we ensure the crane is anchored firmly. The anchors into the floor must be specialized chemical anchors that have a large tensile load capacity since those anchors have to withstand forces attempting to withdraw the anchors from the floor. This type of floor loading is called moment loading. For moment loading, the concrete flooring has to have a specific area around the baseplate that is free of cracks or seams. It has to be at least 6” thick and has to have standard wire mesh embedded within it. Ordinarily, these requirements can be met in most typical factories.
Meeting Moment Loading Requirements
Exactly the same moment loading requirement is met routinely in jib cranes and manipulators. With any moment loading, the crane and its attachment to the floor has to be approved by a licensed professional engineer.
In this photo, a cantilevered bridge crane is suspended from 4 columns, which apply a less severe loading on the concrete. Notice that the runways (the fixed rails) use our rail-on-rail reinforcement for longer spans.
Professional Engineering for Crane Stability
In any cantilevered bridge crane situation, unusual care must be taken during the engineering of the crane to limit deflection and stress. It’s where the experience and skill of the professional engineer comes into play.
Factors in Cantilevered Bridge Crane Engineering
This cantilevered bridge crane uses just 2 columns and large baseplates. I-beams are used as the cantilever beams because the load is small and the overhung distance is not great. Any cantilevered I-beam is susceptible to lateral-torsional buckling, which causes the beam to twist and collapse. This is one more factor to be considered when engineering a cantilevered crane.
The cantilevered bridge crane is an extremely useful option in any production layout. It can be applied in most situations, provided that loads are light and there is ample room at the baseplates to spread the load.
Customized Crane Solutions Tailored for Your Needs
We can engineer, design, fabricate and install a cantilevered crane to fit your requirements.
Questions about how we can help design a unique solution for your business? Send us an inquiry, or call anytime.