Calculate chequer plate load
Deflection, stress and load capacity as a guide value. Does not replace a structural calculation.
1 kN/m² ≈ 100 kg/m². 1 kN ≈ 100 kg.
Safety
Rp0,2 Aluminium (AlMg3): 80 N/mm² (EN AW-5754 H114, EN 1386), E = 70,000 N/mm².
Borderline Borderline: check a thicker sheet or a shorter span.
- Deflection f
- 4.94 mmL/122 · Borderline
- Bending stress σ
- 23.0 N/mm²43 % of 53 · Good
- Load capacity (guide value)
- 1.16 kN/m²
How the calculator works
Linear elastic, static load. Only the base sheet t is used in the calculation. Self-weight g = ρ · t · 9.81.
| Support | Load | Deflection f | Stress σ |
|---|---|---|---|
| Supported on two sides | Area q | 5·q·B·L⁴ / (384·E·I) | q·B·L² / (8·W) |
| Point F | F·L³ / (48·E·I) | F·L / (4·W) | |
| Fixed on two sides | Area q | q·B·L⁴ / (384·E·I) | q·B·L² / (12·W) |
| Point F | F·L³ / (192·E·I) | F·L / (8·W) | |
| Supported on four sides | Area q | α·q·b⁴ / (E·t³) | β·q·b² / t² |
- Two-sided: sheet strip as a beam, I = b·t³/12, W = b·t²/6. Area: b = B. Point: b = min(B; c + L/2).
- Four-sided: rectangular plate, b = short side, ν = 0.3. Coefficients after Roark, table 11.4, case 1a (a/b 1: β = 0.287, α = 0.044). Point load: equivalent two-sided over b.
- Rating: stress up to 80 % of Rp0.2 / 1.5 good, up to 100 % borderline. Deflection up to L/200 good, up to L/100 borderline.
- Not included: impacts, vibration, fatigue, fastening, buckling, corrosion.
Guide value for selection – does not replace a structural calculation.
Example: aluminium 5.0/6.5 mm, 600 mm span
- q = 2 kN/m², B = 1,000 mm, L = 600 mm, t = 5.0 mm (without self-weight).
- F = 0.002 · 600 · 1,000 = 1,200 N; I = 1,000 · 5.0³ / 12; W = 1,000 · 5.0² / 6.
- f = 5 · F · L³ / (384 · E · I) = 4.63 mm (L/130).
- σ = F · L / (8 · W) = 21.6 N/mm² (40 % utilised).
Frequently asked questions
How much does a chequer plate carry?
That mainly depends on span, base sheet thickness and support. The load capacity falls with the square of the span, the stiffness even with the fourth power. The calculator shows the largest load at which stress and deflection stay in the green range.
Why does the calculator only use the base sheet?
The ribs are short and not continuously connected. They hardly carry any load. Using the base sheet keeps the result on the safe side. For “2.0/3.5 mm”, 2.0 mm is the base sheet and 3.5 mm the total height.
Which deflection is permissible?
For walkable covers, L/200 is a common guide value. For a 600 mm span that is 3 mm. More feels soft when walked on.
What does point load mean?
A load on a small area, for example a foot, a wheel or an equipment foot. The sheet spreads it over a limited width only. The calculator uses load width plus half the span for this.
Does the result replace a structural calculation?
No. It is a guide value for selection. For components with loads from people or vehicles or a risk of falling, you need a structural calculation according to the applicable standards.
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