Steel Beam Load Capacity: How to Calculate & Choose the Right Beam
Calculating beam load capacity is critical for structural safety. This guide covers the fundamentals.
Core Formula
Bending Stress: sigma = M / S where M = bending moment, S = section modulus. Beam is adequate when sigma is less than or equal to Fy (yield strength).
Common Configurations
| Config | Max Moment | Max Deflection |
|---|---|---|
| Simply supported, UDL | wL2/8 | 5wL4/384EI |
| Simply supported, center point | PL/4 | PL3/48EI |
| Cantilever, UDL | wL2/2 | wL4/8EI |
Deflection Limits
Floors: L/360 (live load), L/240 (total). Roofs: L/180. For 6m span: L/360 = 16.7mm max.
Selection Process
1. Determine loads (dead + live + environmental). 2. Calculate max moment and shear. 3. Select trial beam: S = M/Fy. 4. Check deflection. 5. Check shear. 6. Check lateral-torsional buckling.
CoreMetal supplies H-beams, I-beams, and structural sections. Contact us for sizing assistance.
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