Free Beam Deflection Calculator
Compute the maximum midspan deflection of a simply supported beam under a uniform distributed load.
Maximum Deflection
5.049 mm
Maximum Deflection vs Distributed Load (w)
How Beam Deflection Works
For a simply supported beam carrying a uniformly distributed load, the peak deflection occurs at midspan.
Governing Equation
delta_max = (5 w L^4) / (384 E I)
where w is the load intensity in N/m, L is the clear span, E is the material stiffness (elastic modulus), and I is the second moment of area of the cross-section. Engineers often check that the span-to-deflection ratio exceeds code limits (commonly L/360 for floor beams).
Example Calculation
A W200x46 steel beam spanning 6 m carries 5 kN/m uniformly.
- 01Convert E: 200 GPa = 200 x 10^9 Pa
- 02Convert I: 8356 cm^4 = 8356 x 10^-8 m^4 = 8.356 x 10^-5 m^4
- 03Numerator: 5 x 5000 x 6^4 = 25000 x 1296 = 3.24 x 10^7
- 04Denominator: 384 x 2 x 10^11 x 8.356 x 10^-5 = 6.417 x 10^9
- 05delta = 3.24 x 10^7 / 6.417 x 10^9 = 0.00505 m = 5.05 mm
- 06Span/deflection = 6000 / 5.05 = 1188 (well above L/360 = 16.7 mm limit)
Frequently Asked Questions
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