Bar Grating Load Capacity Calculator
Calculate the maximum allowable uniform distributed load (UDL) and point load for any steel bar grating specification. Supports NAAMM MBG 531 (allowable stress method) and BS 4592 (UK limit state). Bending and deflection checks included.
Bearing Bar Specification
Span & Design Conditions
Distance between support centrelines
Calculation Method
Section Modulus (per bar):
S = T × H² / 6 (mm³)
Moment of Inertia:
I = T × H³ / 12 (mm⁴)
Bars per metre width:
n = 1000 / P_bb
NAAMM allowable stress:
σ = 0.55 × f_y (MPa)
UDL allowable (kPa):
q = 8·σ·S·n / (L²·1000)
Deflection check (NAAMM):
δ ≤ L / 180
E = 200,000 MPa. Fixed ends use coefficient 16 (bending) and 384 (deflection). Results are simplified allowable-stress estimates — always verify with a structural engineer.
Load Capacity Results
NAAMM MBG 531Max Allowable UDL
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Max Point Load (per m width)
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Deflection at Max Load
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Governing Check
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BS 4592 Load Class
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Results are theoretical estimates using simplified beam theory. Always verify structural adequacy with a qualified engineer before installation.