How to Specify a Rack Beam (Complete Structural Engineering Guide)

Learn about how to specify a rack beam (complete structural engineering guide) in roll forming machines. Profile Guide guide covering technical details

Complete Structural & Manufacturing Guide

Rack beams are used in:

✔ Pallet racking systems
✔ Industrial storage racks
✔ High-bay warehouses
✔ Automated storage systems

They support:

Pallet loads
Uniform distributed loads
Dynamic forklift loads

Rack beam selection must consider:

✔ Span
✔ Load
✔ Deflection limit
✔ Connector compatibility
✔ Code requirements

1️⃣ What Defines a Rack Beam?

A rack beam is defined by:

✔ Section height
✔ Section width
✔ Reinforcement folds
✔ Thickness
✔ Steel grade
✔ Connector type
✔ Span length
✔ Load rating

Without these, the beam cannot be engineered.

2️⃣ Section Geometry

Common beam shapes:

Step beam (most common)
Box beam
Sigma-style reinforced beam
Double C box configuration

Step beams include:

✔ Horizontal step to support decking
✔ Top flange
✔ Bottom flange
✔ Return lips

Geometry directly affects bending capacity.

Never specify only “100 mm beam.”

Full cross-section must be defined.

3️⃣ Section Height (Depth)

Common beam heights:

80 mm
100 mm
120 mm
140 mm
160 mm

Greater height:

✔ Increases bending capacity
✔ Reduces deflection

Height selection depends on:

Span + load.

4️⃣ Span Length

Typical spans:

1800 mm
2400 mm
2700 mm
3000 mm
3600 mm

Longer span increases:

Bending stress
Deflection
Connector stress

Beam must be calculated for its span.

5️⃣ Thickness Range

Common thickness:

1.5 mm
1.8 mm
2.0 mm
2.5 mm
3.0 mm

Heavier industrial racks use thicker beams.

Machine must support:

Maximum thickness + high-strength steel.

6️⃣ Material Grade

Common grades:

G350
G450
G550

Higher grade:

✔ Improves load capacity
✔ Reduces weight

But increases:

Forming load
Springback
Tool wear

Grade must be declared before tooling design.

7️⃣ Connector Type (Critical)

Beam ends include connectors that attach to uprights.

Common connector types:

✔ Teardrop connector
✔ Tab connector
✔ Hook connector
✔ Welded plate connector

Connector must match:

Upright hole pattern exactly.

Small tolerance error makes system incompatible.

Connector welding or punching must be defined.

8️⃣ Load Rating Requirement

Before selecting beam size, define:

✔ Maximum pallet weight
✔ Number of pallets per beam
✔ Load type (uniform or point load)
✔ Impact factor
✔ Deflection limit (often L/200 or L/180)

Beam must be structurally calculated.

Never estimate based on height alone.

9️⃣ Deflection Criteria

Typical deflection limits:

L/180
L/200
L/250

Excess deflection causes:

Pallet instability
Safety risk
Code non-compliance

Deflection often governs design more than strength.

🔟 Safety Lock Requirement

Many beam connectors include:

✔ Safety locking tab
✔ Secondary locking mechanism

Safety lock prevents accidental beam disengagement.

Must be specified for compliance.

1️⃣1️⃣ Coating & Finish

Common finishes:

Powder coated
Pre-galvanized
Hot-dip galvanized

Interior warehouse commonly uses powder coating.

Cold storage or corrosive environments may require galvanizing.

Finish impacts:

Appearance
Corrosion resistance
Market preference

1️⃣2️⃣ Typical Coil Width

Coil width =

Web + 2 flanges + returns + reinforcement folds + bend allowance.

Example simplified:

100 mm web
40 mm flange ×2
20 mm returns ×2

100 + 80 + 40 = 220 mm
Add bend allowance → approx. 240–280 mm

Box beams require wider coil.

Exact developed width must include:

✔ Bend radii
✔ Thickness compensation
✔ Springback correction

Never approximate coil width.

1️⃣3️⃣ Machine Engineering Requirements

Rack beam line:

14–24 forming stands
70–100 mm shafts
22–55 kW motor
Connector punching station
Welding station (if welded connector)
Hydraulic cut-off

High-strength material increases shaft and motor requirement.

Punching at beam ends requires precise servo system.

1️⃣4️⃣ Production Speed

Typical speeds:

10–25 m/min

Connector punching and welding often limit speed.

1️⃣5️⃣ Tolerance Requirements

Typical tolerances:

Height ±1 mm
Width ±1 mm
Connector alignment ±0.5 mm
Length ±2 mm

Connector misalignment causes installation failure.

Precision is critical.

1️⃣6️⃣ Seismic Considerations

In seismic regions:

✔ Higher safety factors
✔ Stronger connectors
✔ Reduced deflection limits
✔ Locking mechanism mandatory

Beam design must align with seismic code.

1️⃣7️⃣ Common Specification Mistakes

❌ Not defining connector type
❌ Ignoring span
❌ Not defining load clearly
❌ Underestimating deflection requirement
❌ Using too thin material
❌ Guessing coil width

Rack beam failures are structural and high liability.

1️⃣8️⃣ Developed Width Reminder

Developed width must include:

✔ Web
✔ Flanges
✔ Reinforcement folds
✔ Step detail
✔ Bend allowance
✔ Thickness compensation
✔ Springback correction

Complex beams require precise flat pattern calculation.

1️⃣9️⃣ Final Rack Beam Specification Checklist

Before tooling or machine approval:

✔ Confirm full cross-section geometry
✔ Confirm section height
✔ Confirm thickness range
✔ Confirm steel grade
✔ Confirm connector type
✔ Confirm connector tolerance
✔ Confirm span length
✔ Confirm load rating
✔ Confirm deflection criteria
✔ Confirm coating
✔ Calculate developed width
✔ Confirm coil availability
✔ Confirm production speed target
✔ Confirm code compliance

Only then proceed.

FAQ Section

Is beam height more important than thickness?

Both matter — height increases stiffness more efficiently.

Does connector type matter?

Critical — must match upright system exactly.

Can beam thickness be reduced if grade increases?

Possibly — but must be structurally calculated.

Is welding required?

Some systems use welded end plates; others use punched tabs.

Are rack beams heavily punched?

End connectors are punched; body usually not.

Can one machine run multiple beam sizes?

Yes with adjustable tooling and proper design.