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Structural engineering, Advanced
Beam Deflection
Maximum mid-span deflection of a simply-supported beam
Formula: deflection = PL³ ÷ 48EI (centre-point load, simply supported)
Maximum mid-span deflection of a simply-supported beam under a centre-point load — PL³/(48EI). Compare against L/360 serviceability limit to ensure the beam won't visibly sag in service.
Inputs
Results
Maximum Deflection
0.006349 m
Recommended next actions
- →Use a deeper section to reduce deflection (I scales with depth^3)
- →Check shear and bending stress separately
Turn this result into an action plan
Send the calculation to your inbox or book a review if the numbers point to cost, compliance, or uptime risk.
Formula
deflection = PL³ ÷ 48EI (centre-point load, simply supported)Worked example
Inputs
load5000
length4
elastic_modulus210000000000
moment_of_inertia0.000005
Outputs
deflection0.00635
Use for estimation. Verify safety-critical calculations with qualified review.