When it comes to selecting the right Electric Overhead Traveling (EOT) crane for lifting a 20-ton load, one of the most important decisions you will face is whether to go for a single girder or double girder design. Both types of EOT cranes are widely used across industries such as manufacturing, construction, logistics, and steel fabrication, and each has its own advantages and limitations depending on the application.
In this article, we will explore the key differences between single girder and double girder EOT cranes, evaluate their performance in the context of a 20-ton load, and guide you in choosing the most suitable option based on capacity, cost, design, installation, and long-term use.
Understanding the Basics
Single Girder EOT Crane
A single girder EOT crane consists of one main bridge girder supported by end trucks. The hoist and trolley operate on the bottom flange of the girder, typically using a under-running or top-running configuration.
Double Girder EOT Crane
A double girder EOT crane features two main girders with a crab-type trolley that runs on rails mounted on the top of the girders. This design allows for better hook height and increased load-bearing capability.
Load Capacity Considerations
While single girder EOT cranes can lift loads up to around 20 tons, this capacity lies at the upper limit of their range. Most single girder cranes are typically used for loads between 1 ton and 15 tons. Pushing a single girder crane to handle 20 tons requires heavy reinforcement, making it less efficient from a structural and cost perspective.
Double girder EOT cranes, on the other hand, are well-suited for 20-ton loads and beyond. Their design naturally accommodates higher capacities with better load distribution and stability.
✅ Verdict:
- For 20 tons, a double girder EOT crane is generally more appropriate in terms of strength, safety, and long-term performance.
Hook Height and Lift Distance
Hook height is the distance from the floor to the hook when it is at its highest lifting point.
- Single girder cranes have a hoist that hangs below the girder, which reduces the maximum possible hook height.
- Double girder cranes allow the hoist to be mounted between the girders, gaining extra vertical space for lifting.
This makes a double girder crane more suitable for situations where high lifting height is required, such as in tall industrial buildings or when lifting large machinery that occupies vertical space.
✅ Verdict:
- If you need maximum lifting height, go for a double girder crane.
Span and Crane Travel Length
Both crane types can be used for long spans, but double girder cranes are better suited for spans above 20 meters due to their structural rigidity.
- For a 20 ton overhead crane with a wide span, a double girder system provides better load stability and less deflection.
- Single girder cranes may suffer from excessive beam deflection at larger spans unless reinforced, which adds cost and complexity.
✅ Verdict:
- Double girder cranes handle wider spans and longer travel lengths more efficiently.
Installation and Building Structure Requirements
- Single girder cranes are lighter and easier to install, requiring less robust supporting structures.
- Double girder cranes are heavier and require a stronger runway beam and more robust support columns, potentially increasing installation complexity and cost.
If the building is not originally designed for heavy equipment or has height limitations, single girder cranes may be easier to integrate.
✅ Verdict:
- For existing buildings with limited structural capacity or headroom, single girder cranes could be more feasible.
Cost Considerations
Cost is always a key factor in equipment selection.
- Single girder cranes are generally 20-30% less expensive than double girder cranes due to fewer components and easier manufacturing.
- However, when designed to lift 20 tons, the cost of reinforcing a single girder crane can significantly narrow this gap.
- Additionally, double girder cranes offer greater long-term value for higher load applications due to reduced wear and better component longevity.
✅ Verdict:
- Initial cost advantage lies with the single girder crane, but double girder cranes may offer better return on investment for continuous or demanding operations.
Operational Environment and Frequency of Use
If your crane is used occasionally or for light-duty operations, a single girder crane may suffice for a 20-ton load (assuming the structure and hoist are appropriately rated). However, for frequent lifting, heavy-duty cycles, or harsh working conditions, double girder cranes are more durable and reliable.
Common applications of 20-ton double girder cranes include:
- Steel coil handling
- Foundry and furnace feeding
- Concrete precast lifting
- Heavy machinery assembly
- Shipbuilding and port applications
✅ Verdict:
- For high-frequency or industrial-grade use, a double girder EOT crane is the better choice.
Maintenance and Safety
- Single girder cranes offer easier access for maintenance since the hoist is mounted below the girder.
- Double girder cranes require more effort to access the hoist and trolley, but they support redundant safety features, such as walkways, railings, and advanced monitoring systems.
Additionally, anti-sway technology, overload protection, and automation features are more commonly integrated into double girder systems due to the available space and structural support.
✅ Verdict:
- Double girder cranes are more customizable with advanced safety features, making them ideal for demanding operations.
Customization and Future Scalability
If your facility is expected to grow or if you might need to handle heavier loads in the future, a double girder crane offers more scalability. Its design allows for:
- Adding a second hoist
- Increasing lifting speed
- Integrating automated systems
A single girder crane will be more limited in these aspects and may need complete replacement if capacity requirements increase.
✅ Verdict:
- Choose double girder cranes for future expansion or customization.
Conclusion: Which One Is Right for a 20 Ton Load?
For 20-ton loads, especially in medium to heavy-duty industrial applications, a double girder EOT crane is the recommended choice. It offers better performance, safety, scalability, and long-term reliability.
However, if your application is infrequent, the lifting height is not critical, and budget is a primary concern, a reinforced single girder EOT crane may be a viable and cost-effective solution—provided that all structural and operational considerations are carefully evaluated.
Always consult with a professional EOT crane manufacturer or structural engineer to assess your specific site conditions and operational needs before making a final decision.
