This blog post will be part of a two-post series on bridge crane types. In this first part, we will be discussing Single Girder Overhead Bridge Cranes and their benefits and drawbacks. The second part will discuss Double Girder Overhead Cranes. First, a few basics. A bridge crane is a type of overhead crane which includes at least two overhead runways that are built into the support structure of a building. The bridge is the load bearing beam that runs the width of the bay and is the structure that connects the runways and moves the hoist. The number of beams, one or two, gets us to the single or double girder configuration. As you can guess, an overhead crane with one beam is a single girder design.
The design selection of an overhead crane system is one of the largest factors in the complexity and cost of the system. Because of this, it’s important to carefully consider which type of configuration will work in your application. With a single girder crane, the bridge comprises of a single girder beam supported by an end truck on each side. The bridge can be top running or under running and the trolley and hoist are usually underhung.
A single girder crane is generally used in applications that need light to medium duty cranes or buildings where headroom is limited. In general, a single girder crane offers more cost-savings than a double girder crane because they are usually lighter and don’t require as much material to manufacture. This means you save on freight, installation, and material costs.
These cost savings do come with a drawback. Single girder cranes have a limit on capacity, span and hook height. Special features such as walkways and operator cabs are also more difficult and costly to include in a single girder crane design.
If you need an overhead crane with a capacity over 15 tons and a span greater than 65 feet or a crane with special features, a double girder crane will most likely be a better solution. A single girder crane can be rated higher than 15 tons, but it’s not a common practice to use a single girder crane in that type of application because of cost.
The advantages and disadvantages of a single girder configuration are listed below. If you have any questions about which configuration is right for your application, feel free to contact us via email or give us a call at (800) 509-6131. Already know what you're looking for? Head over to our request a quote page to get your custom quote.
- Easier installation, service and maintenance
- Lower production costs
- Usually the most cost-effective option for light to medium duty cranes
- Works well for buildings where headroom is limited
- Lower overall weight can reduce support structure cost or can be supported by existing building structure
- Special features such as walkways and operator cabs are more difficult to include
- Reduced hook height compared to double girder cranes
- Capacity rating is lower
- Trolley wheels ride on the main girder bottom flange which may cause more wear to the bottom flange of the beam