Box girders
A box girder is an enclosed, four-sided tube made from multiple walls. Unlike an I-beam or H-beam, a box girder contains multiple vertical webs. Double girder cranes built from two box girders usually feature a pair of box girders with the trolley and hoisting mechanism operating on rails attached to the tops of each box girder. Single girder cranes are built using a single box girder with the trolley and hoisting mechanism running on the lower flange of the box girder.
Some overhead crane manufacturers, such as GH Cranes & Components, custom build their cranes from box girders rather than wide flange beams. The advantages of this technique are many.
- Lower cost of steel: Building with box girders requires less steel. One of the main costs of an overhead crane is the materials used in its manufacture and the less steel that is needed, the lower the cost of steel in the crane.
- Lower weight: Overhead cranes built from box girders are also lighter than comparable cranes built from structural steel. Columns can be lighter weight, runway beams can be lighter, and the building structure can be a lighter weight overall.Also, the lower weight of the box reduces the structural requirements of the runway design by lowering the crane loads on the runways and support columns.
- Better hook height: Another advantage of box girder cranes, whether single girder or double girder, is that they enable you design the girder depth to improve hook height.
- Greater loading capability: A further advantage of box girder cranes is that they possess greater loading capabilities and are able to span longer bridge distances than their structural-steel counterparts.
- Greater design flexibility: Steel buildings need to be designed to loading requirements. When you determine the load of your crane, you also consider the dead load (on the building all of the time) and the live load (on the building when the crane is lifting or moving a load). The advantage of overhead cranes built from box girders is that they give you more design flexibility, since they are lighter than comparable cranes built from wide flange beams.
If you are getting ready to design or erect a steel building, you likely understand that a number of factors affect your cost of materials.
One of those factors is the engineering requirements for your building to meet local wind, snow and seismic code requirements as well as loading requirements. But have you considered that the type of overhead crane you install in your steel building also affects your price?
Consider installing an overhead crane built from box girders. You’ll enjoy lower costs, greater design flexibility and greater loading capacity.
