EOT Crane Deflection Calculator

Verify crane girder stiffness and natural frequency against IS/FEM standards.

1. Configuration & Loads

meters

kN (SWL + Trolley)

kN

2. Girder Section Properties

cm⁴

GPa (Steel)

Verification Status

COMPLIANCE REPORT

Total Deflection: 0.0 mm
--
Allowable Limit: 0.0 mm
Dead Load Deflection: 0.0 mm
Live Load Deflection: 0.0 mm
Utilization 0%
Dynamic Response
Natural Frequency: 0.0 Hz
Min Req: > 2.0 Hz
Checks against IS 807 / FEM 1.001

Limits

Electric cranes typically restricted to Span/750. Manual cranes Span/500. Precision applications require stricter Span/1000.

Load Case

Calculates worst-case static deflection (Trolley at center) + Dead load deflection. Dynamic factors are applied to structural stress, usually not deflection.

Vibration

Natural frequency should ideally be > 2Hz to avoid resonance with swinging loads and operator discomfort.

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Understanding Crane Deflection

Deflection is the vertical bending of the crane girder under load. Excessive deflection can cause trolley travel issues, wheel wear, and operator discomfort. This calculator verifies if your girder design meets the stiffness requirements of IS 807 and FEM 1.001.

Inputs Explained

  • Crane Span: The distance between the runway rails.
  • Total Live Load: The weight of the lifted load (SWL) plus the weight of the trolley/hoist.
  • Total Bridge Weight: The weight of the girder(s) and end carriages.
  • Moment of Inertia (Ix): A geometric property of the girder section that represents its resistance to bending. Higher Ix means less deflection.
  • Limit Standard: The allowable deflection ratio (e.g., Span/750). Stricter limits apply to higher duty or precision cranes.

Outputs Explained

  • Total Deflection: The sum of deflection due to Live Load (worst case at center) and Dead Load (self-weight). Note: Standards often limit Live Load deflection separately.
  • Utilization: The percentage of the allowable limit used by the calculated deflection.
  • Natural Frequency: The frequency at which the girder naturally vibrates. Should be > 2 Hz (or > 3 Hz for high speed) to avoid resonance.