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Bending I-Beam and U Channel With Ladder cable trays

We’ve covered everything you need to know about the ladder cable trays.  You should also check out our Bending Cable Tray to 90 Degree Horizontal page.

We’ve got you covered when it comes to Bending I-Beam and U Channel in your ladder cable trays project.
With a variety of options available, it’s important to make sure that your parts work within the guidelines to ensure a successful fit. BIT is proud to recommend PBA Aluminum Bending Machine for your project.

Ladder cable trays

Ladder cable trays are a type of cable management system comprising two longitudinal channels connected by horizontal rungs. Typically constructed from stainless steel, aluminum, or FRP, they feature various surface treatments like hot-dipped galvanized or powder coating, offering ample space and excellent ventilation. Their fire-resistant nature makes them ideal for industries such as paper mills, power plants, and oil & gas facilities.

An innovative I-Beam steel rail design enhances performance, enabling these trays to carry up to 2.3 times more load than traditional C-channel trays while reducing weight by an average of five percent. This design also facilitates easy installation of splice plates and accessories.

They boast a robust structure, corrosion resistance, and high loading capacities, and are suitable for various applications except elevator shafts. Available in different materials, sizes, and configurations, ladder cable trays offer durability, efficiency, and longevity for cable management needs in diverse environments.

Features

  • Ladder cable trays have robust structures for laying cables of any sizes.
  • Ladder cable trays resist corrosion, and heat due to hot-dipped galvanized, pre-galvanized, powder coated surface.
  • High loading capacities.
  • Excellent air ventilation property due to the spacious ladder type.
  • Used in all locations except elevator shafts.
  • Various components are connected by accessories.
  • Beautiful structure. Ladder cable trays’ side channel types include C channel, and I-beam channel.
  • Longer service life.

Specification

  • Material: stainless steel 304/316, aluminum alloy, FRP.
  • Surface treatment: hot-dipped galvanized, pre-galvanized, epoxy coated, powder coated.
  • Length: The standard length is 2500mm.
  • Width: 100mm – 1200mm.
  • Thickness: 1.5mm – 2.0mm.
  • Side runner height: 50mm, 75mm, 100mm, 150mm.
  • Rung width: 35mm, 50mm.
  • Rung spacing: 150mm – 300mm.
  • Load capacity: 30kg/m – 90kg/m.
  • Structure and accessories: horizontal inward, inside riser, outside riser, tees, reducers, coupler plate, fasteners, end claps.

I Beam Cable Tray

The I-Beam cable tray design is another side rail style offered besides C-Channel side rail styles for customers that prefer this style. One advantage of I-Beam ladder cable trays is that hold-down clips and expansion guides can be located inside or outside the I-Beam cable tray.

  • I-Beam cable tray is available in all NEMA load classes and CSA load classes. Some
  • I-Beam trays can carry over 100 pounds per foot on spans up to 30′.
  • A full complement of fittings accessories and support material is available.
  • Straights and fittings include splice connectors and hardware (except the basket tray)
  • The material is 6063 T6 Aluminum for side rails, rungs, and splice connectors.
  • Width: 6″, 9″, 12″, 18″, 24″, 30″, 36″, 42″ and 48″
  • Ladder Rung Spacing: 6″, 9″, 12″ and 18″
  • Trough Bottoms: Corrugated Ventilated, Solid Corrugated Non-Ventilated, 4″ Rung Spacing Ventilated Trough
  • Depths: 4-1/2″, 6″, 7″and 8″
  • Lengths: 10′, 12′, 20′, 24′ and 30″
  • Fitting Radius: 12″, 24″, 36″, 48″, mitered and Square Cornered

Bending Aluminum I-Beam and C Channel Cable Trays

radius bend cable trays
radius bend cable trays

Cable Ladder Horizontal E-Bend

Creates a 90° gradual sweep in the horizontal plane for Cable Runway runs. Designed for cabling in conformance with minimum bend radius requirements (typically 4 times the cable diameter). Made of lightweight 1-1/2″ x 3/8″ tubular steel to fit standard Cable Runways. Cross members welded at approximately 23° increments.

  • Conforms to cable bend radius requirements
  • Easy installation using CPI Butt-Splices (P/N 11301-001, not included)
inside radius bend cable trays
inside radius bend cable trays

Ladder Radius Bend – 90° Inside Bend

Creates a 90° gradual bend for cascading cable runs.

  • Made of lightweight 1-1/2″ x 3/8″ (38.1 mm x 9.53 mm) tubular steel
  • Three cross members welded at approximately 23° increments
  • Outside/Inside is determined by welding cross members closer to the cable side
outside radius bend cable trays
outside radius bend cable trays

Ladder Radius Bend – 90° Outside Bend

Creates a 90° gradual bend for cascading cable runs.

  • Made of lightweight 1-1/2″ x 3/8″ (38.1 mm x 9.53 mm) tubular steel
  • Three cross members welded at approximately 23° increments
  • Outside/Inside is determined by welding cross members closer to the cable side

Deflection

Since the most economical cable tray system utilizes heat-treated aluminum alloys, or high-strength steels with long spans, any limitation on deflection which will not permit the best utilization of material and design will increase the cost. By limiting the maximum fiber and shear stress used in the design the adequacy and safety of the structure are assured.

Why Limit Deflection?

The primary reason to limit deflection in cable tray systems is the appearance of their installations. So rigid restrictions on the deflection of cable trays installed at eye level or in prominent locations are common. However, it is neither economical nor good engineering practice to restrict the deflection of a cable tray system in less prominent areas.

Methods of Decreasing Deflection

There are various ways to limit the deflection of a cable tray. If the objective is minimum installed cost, they should be considered in this order:

Decreasing the Stress by Decreasing the Bending Moment

This can be accomplished by introducing restraining moments at the end of a span in the form of rigid support. The deflection in a continuous beam, with negative bending moments at the intermediate support points, is only a fraction of the deflection in a simple beam.

Increasing the Depth of the Cable Tray

Deflection in any location can be reduced by increasing the depth of the load-carrying side members and/or by adding to their cross-sectional area. Adding to the depth generally utilizes the material most economically.

Increasing the Modulus of Elasticity

Since the modulus of elasticity of steel is 29 x 106 psi, and that of aluminum alloys is only 10 x 106 psi, greater deformation of aluminum alloy trays is to be expected at any given stress level. Under its weight, an aluminum beam will deflect the same amount as an identical steel beam, since not only the weight but also the modulus of elasticity is only one-third that of steel. However, under the same applied load (disregarding the beam’s weight), aluminum will deflect almost three times as much as steel. Therefore consideration must be given to the choice of material for any one location. For an isolated run or an entire installation.

Deflection Criteria Applied to Cable Tray

Design rules and specifications developed for steel should not be applied to aluminum alloys since this would not permit the most economical use of these materials. Deflection criteria which apply only to steel and should not be used when the most economical system is desired, include:

Span-Deflection Ratio

For example, the deflection is limited to 1/300 of the span by the National Electrical Manufactures Association specifications for structures supporting air switches. While very important in that instance as even slight deflection could cause misalignment in the operating mechanism and result in binding and difficult switch operation, the application of this specification to a cable tray system is uneconomic and not recommended.

Depth-to-span ratio

Example: The American Institute of Steel Construction, in their specifications for buildings, specifies the depths of beams and girders in floors to be not less than 1/24 of the span, or not less than 1/20 of the span where shock or vibration may be encountered. This specification ensures a certain rigidity and levelness of the structure which is important in that instance but cannot be justified for cable tray systems because of the higher cost involved.

Deflection Constants

Example: Deflection is limited to a certain amount by an engineering company for a tray system. While such a specification might make a system using 8-foot spans look better, it prohibits the use of more economical designs with longer spans which can have much greater deflections and still look acceptable. Such a specification increases the cost of the tray system unnecessarily, especially if the trays are to be installed well above eye level.

PBA Cable Tray Bending Machine

Cable Tray Bending Machine

Repeatability and Accuracy: Fully servo-driven, higher repeat positioning accuracy, allows for precise control over the aluminum bending, resulting in higher accuracy and repeatability.
Variable Geometry Bending Rolls: Maximizing machine capabilities requires the flexibility of variable centers to accommodate various workpieces.
Springback Compensation Calculation: PBA’s CNC control system by simply testing the actual radius during bending, the springback compensation amount can be determined and inputted into the system, ensuring achieving the desired geometric shape and dimensions during the aluminum bending process.
Ease of Use:
Operators should be able to master complex bending tasks within a single day; Consistent accuracy; Consistent shape production; Simple development of irregular shapes; and Reliability for both low and high volumes.

PBA Aluminum Bending Machine for Cable Tray Bending vs. Conventional Machines

Servo System of Aluminum Bending Machine

Y-axis Positioning Methods

  • Fully servo-driven, with a repeat positioning accuracy of less than 0.01mm, unaffected by temperature;
  • Conventional machines: Driven by hydraulic cylinders, positioning speed and accuracy are easily affected by temperature.
Servo System of Aluminum Bending Machine

Spindle (Y-axis) Rotation Drive

  • Servo motor + planetary gearbox, constant torque, no inertia, high positioning accuracy, high torque transmission efficiency;
  • Conventional machines: Variable frequency drive motor driving gear reducer, transitioning through a universal joint drive shaft, torque increases with speed, large motor inertia, leading to poor system stability and low positioning accuracy.
Horizontal Types of Aluminum Bending Machine

Horizontal Positioning is Preferred

  • PBA aluminum bending machines are vertical spindle and horizontal installations that high-precision bending for aluminum profiles of varying lengths, and are best suited for handling long, narrow workpieces, and also good for creating tight bends without deformities.
  • Vertical aluminum bending machines not suitable for processing very aluminum profiles, can be more difficult to operate and they’re not as precise as horizontal machines.

Notes: When bending large workpieces or large-diameter aluminum profiles, horizontal positioning is preferred. Proper support in the chosen position prevents the weight of the workpiece from affecting the final results. Bending in a horizontal position is also utilized to address clearance issues at customer facilities.

X-axis Variable Center Distance of Aluminum Bending Machine

X-axis Variable Center Distance

  • PBA is the variable geometry aluminum profile bending machine, variable centers adjust the machine to perform like a large or small machine, and are suitable for bending aluminum profiles and for heavy metal fabrication work.
  • Conventional machines: The X-axis center distance of commonly used aluminum profile bending machines for door and window profiles in the market is not adjustable.

Works Cited:

  1. https://www.superiortray.com/tech-docs/cable-tray-deflection/
  2. https://www.mphusky.com/cable-tray/i-beam
  3. https://www.server-rack-online.com/cable-ladder-bends-and-radii.html