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Crane TypeDouble Girder Overhead Crane
The solution for facilities that need high tonnage, wide span and maximum lifting height.
Construction
In a double girder crane the bridge consists of two parallel main girders, usually welded box sections, carrying rails on top for the trolley to run on.
Because the trolley sits on top of the girders, a larger hoist unit can be fitted, the reeving can be arranged more flexibly, and the hook can be raised much higher.
What it gains you
The most visible gain is lifting height; under the same roof it's a clear difference over single girder. The second gain is capacity and span: two box-section girders work far more efficiently over a wide span.
The third is equipment flexibility. A maintenance platform can be fitted between the girders; an auxiliary hook can be added alongside the main hook for lighter work; an operator cabin can be fitted for continuous operation.
Building and runway side
| Criterion | Assessment |
|---|---|
| Tonnage | Moderate to high tonnage |
| Span | Efficient at wide spans |
| Lifting height | Noticeably more than single girder |
| Wheel load | High — building and runway checks required |
| Maintenance platform | Can be fitted |
| Auxiliary hook | Standard option |
| Operator cabin | Can be fitted |
| Duty class | Suited to heavy-duty classes |
Technical terms
| Term | What it means |
|---|---|
| Box girder | A girder cross-section welded from four plates, resistant to torsion. |
| Auxiliary hook | A second hoist unit next to the main hook, for light, fast work. |
| Maintenance platform | A walkway fitted between the girders for safe access to equipment. |
| Open trolley | A trolley type where the hoist unit is mounted in the open, on top of the girders. |
Frequently asked questions
Is double girder always better?
No. At low tonnage, moderate span and infrequent use it means unnecessary weight and cost, and the higher wheel loads place extra demand on the building.
What is the auxiliary hook for?
The main hook is large and slow. Using a separate, faster, lower-capacity hoist unit for small parts cuts cycle time.
Can I fit a double girder crane in my existing building?
Yes, if a structural check confirms the columns and brackets can carry the increased wheel loads. If not, reinforcement or a separate legged runway is needed.