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Mezzanine Beam Size Calculator
Preliminary W-shape selection for mezzanine floor beams. Set span, spacing, and floor loads, then find a light candidate that satisfies simple ASD bending and deflection limits.
Mezzanine Beam Designer
Floor Beam Sizing Automation
1. Geometry & Loads
2. Recommended Section
Optimal Size
W12x16
Weight: 16 lbs/ft
Try reducing span or loads, or add heavier shapes to the database.
Trib Width Used: 0 ft
Total Uniform Load: 0 plf
Max Moment: 0 ft-kips
Required Inertia (Ix): 0 in⁴
Required Section (Sx): 0 in³
Sizing Mezzanine Floor Beams
Mezzanine beams are usually uniformly loaded floor members spanning between girders or columns. Tributary width differs for interior beams (full spacing) versus edge beams (about half). This designer scans common W-shapes for a light section that passes a simplified ASD moment check and your chosen live-load deflection limit — useful for early layout, not a sealed calculation package.
How to use this calculator
- Pick Interior or Edge so the tributary diagram and load width match the beam position.
- Enter span, beam spacing, live load (psf), dead load (psf), and deflection limit (L/360 floors are typical).
- Run Find Lightest Beam and review the recommended section, demand ratios, and deflection before refining in your analysis software.
Load assumptions worth checking
Common live loads: 125 psf light storage, 250 psf heavy storage, 50 psf offices (+partitions), 100 psf assembly. Dead loads often include 10–15 psf grating/plate, 50–60 psf for concrete on deck, plus collateral MEP. Vibration, concentrated rack posts, and partial composite action are outside this tool — escalate those to a full model.
FAQ
Is this a substitute for engineered design?
No. It is a preliminary selector. Confirm bracing, connections, lateral systems, and code combinations with a licensed engineer.
Why does edge vs interior matter?
An edge beam typically takes roughly half the floor strip of an interior beam at the same spacing, so the required section can be lighter — unless facade or guard loads add more.
When should I use L/480?
When finishes are sensitive to bounce or cracking (brittle ceilings, precise equipment). Many industrial mezzanines use L/360 for live load.
Are self-weight and camber included?
Dead load input should include deck/slab and an allowance for the beam itself if not added automatically in your workflow. Camber is a fabrication decision after final design.
Where this fits in the workflow
- AISC Steel Shape Database Check the section properties behind the beam the tool suggests.
- Bar Joist Size Database Frame the deck between the beams with bar joists.
- Crane Beam & Monorail Calculator Stricter deflection limits when the load is a hoist rather than a floor.
- Stair Stringer & Headroom Calculator Access to the mezzanine still has to meet rise and run rules.
Read the longer write-up
- Crane Runway Deflection: L/450 vs L/600 for Estimators Deflection often governs light industrial runway beams before bending stress does. What CMAA-style limits mean for preliminary sizing and shape selection.
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