Top running overhead cranes have a rail that runs on the top of each runway beam. This allows the end trucks to carry the bridge across the top of the runway, as opposed to running underneath on the bottom flange (Underhung Cranes). Top running cranes allow the weight of the crane and live load to be put onto the floor instead of applying that weight to the roof trusses. This is done with either a freestanding system of columns and runways, or in some cases, haunches can be added to existing building columns and runways are placed on those haunches.
At TC/American, we manufacture two types of top running cranes, Box Girder and Wide Flange. Both of these styles can be designed as a single or double girder.
For both Wide Flange and Box Girder top running cranes, the hoist and trolley travels on the bottom flange for a single girder, while they travel on top.
Wide Flange Construction
Wide flange top-riding cranes are designed with an “I-Beam” style structural girder. This girder is composed of plate steel fabricated to include a top flange, bottom flange, and web plate. This overhead crane design is ideal for freestanding, short span, or low capacity cranes.
Wide flange cranes can be stretched out to longer spans or higher capacity if needed, but as the span and capacity increase, the size of the girder gets deeper and heavier. This can cause unneeded stress to the shop floor or building columns and can often surpass what the floor or columns are rated for.
When the weight starts to become an issue, this is when you would start to look at a box girder design.
Box Girder Construction
Box girders are similar to a Wide Flange overhead crane in functionality, but much different in design.
These cranes are manufactured with plate steel as well, but are fabricated into a box with internal baffles and stiffeners, creating a stronger construction than wide flange, but providing a lower weight per foot.
TC/American is currently manufacturing Box Girder Overhead Cranes up to 140’ span, and up to 150 Ton Capacity. These are our standard capabilities, larger cranes are possible but will require further engineering to assess plausibility.
We also offer several different options when it comes to completing the crane. We can:
Fabricate and assemble the entire crane utilizing TC/American box girders, and Jaso Industrial Crane components.
Fabricate and assemble the crane utilizing TC/American box girders, but you provide the crane kit and components of your choosing.
Fabricate just the box girders themselves and send you “naked boxes” for you to paint and assemble in your shop.
