When G-RailTM bridge cranes are hung from overhead, a variety of hangers can be used, depending on the situation.
Typically, but not always, cranes are hung from an overhead structure made of I-beams or from roof joists. Roof joists are usually comprised of 2 angles running horizontally (the “bottom chord”) back-to-back, in essence forming a shape similar to the bottom of an I-beam.
So, most overhead steel can be clamped by the lower flange of an I-beam, or a similar shape.
Low Steel Hangers
Often, an overhead structure already exists that a crane can be hung from, especially in the case where a crane has to run alongside an auto assembly line. Usually, this steel is relatively “low” and a hanger is needed to keep the runways as high as possible against the steel. This is where the versatile Low-Steel Hanger (LSH) is used. The low-steel hanger clamps tightly against the bottom of an I-beam and clamps into the top of a G-Rail.
Givens Low-Steel Hangers are specially designed to maximize the height of the crane runways, providing as much valuable working height as possible. Typically, most models allow the G-Rail to come as close as 1” to 2” to the I-beam underside! And, the height is adjustable, which is essential when the levelness of the steel is unknown. No other crane hangers bring the rail so high to the steel and still offer adjustability.
Types of Low Steel Hangers
Low-Steel Hangers are offered in 2 versions: the “Parallel” and the “Perpendicular”, to accommodate overhead steel that runs parallel to or perpendicular to the crane runways. In general, it is preferable to have the steelwork run perpendicular to the runways because that arrangement offers the greatest adjustment in the positioning of the crane.
Perpendicular low-steel hanger
There are Low-Steel Hangers for each model of G-Rail:
- C250-LSH-PL: For 250 and 100-kg G-Rail Parallel configuration
- C250-LSH-PP: For 250 and 100-kg G-Rail Perpendicular configuration
- C1000-LSH-PL: For 500 and 1000-kg G-Rail Parallel configuration
- C1000-LSH-PP: For 500 and 1000-kg G-Rail Perpendicular configuration
- C2000-LSH-PL: For 2000-kg G-Rail Parallel configuration
- C2000-LSH-PP: For 2000-kg G-Rail Perpendicular configuration
Low Steel Hanger Dimensions
|Low Steel Clamp||C100/C250||C500/C1000||C2000|
|Capacity||400 kg||1400 kg||2500 kg|
|Minimum Beam Flange Width||3.5” – Parallel 4” – Perpendicular||5” – Parallel 4.9” – Perpendicular||4.55” – Parallel 4.4” – Perpendicular|
|Minimum Beam Flange Thickness||0.2”||0.34”||0.31”|
|Maximum Beam Flange Width||7”||8”||8”|
|Maximum Beam Flange Thickness||0.5”||0.72”||0.75”|
The other case is where the crane has to be hung from steel that is much higher than the crane. Normally, the crane should be hung at a height of 2.75m to 4m but often, the steel work is much higher, perhaps 7m or 8m. In most cases, light cranes are not hung this high because it is difficult to make the bridge move by pulling from so far below.
Our Solution to High Steel Hangers
The overhead steelwork may be extremely complex, with a combination of trusses and I-beams, with interfering ducts and conduit. Givens has developed a set of extremely versatile components to accommodate most situations, often involving improvising and cutting on-site, without knowing accurate overhead dimensions.
Every crane in a high-steel situation should have “diagonals” that prevent sway in both the east-west and the north-south directions. Without diagonals, repeated sway over years can cause fatigue damage and hanger failure.
High Steel Hanger Dimensions
|High Steel Hanger||C100/C250||C500/C1000||C2000|
|Capacity||600 kg||1700 kg||3000 kg|
|Minimum Beam Flange Width||3.5”||4”||4.5|
|Minimum Beam Flange Thickness||0.2”||0.2”||0.25”|
|Maximum Beam Flange Width||6.75”||11”||10.5”|
|Maximum Beam Flange Thickness||0.5”||0.76”||0.76”|
Plate hangers are the simplest form of hanger, but they lack the feature of vertical adjustability. They can only be used in situations where the overhead steelwork is known to be absolutely level. The underside of a mezzanine is an example of steelwork that is very likely to be flat and level.
Plate hangers (in black in the photos) are typically made custom for the job at hand and are normally made to suit the thickness of the I-beam flange.
Of course, none of the above-described hangers would apply if there are columns present where we would be installing the bridge crane hanger. When columns exist, the runways will be supported by horizontal headers, using saddles, as shown here:
Trust Givens Engineering for a Customized Solution
Have any questions about how your crane might be hung, or need a customized solution for your business? Reach out to the Givens Engineering team for a quote on bridge crane hangers!
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