Jib Crane Deflection Calculator

The jib crane deflection calculator estimates downward jib bending under lifted loads to check operational safety. With core parameters including jib cantilever beam effective slewing radius and column effective height, it validates compliance with ISO, GB and related standard limits. Excessive deflection triggers load swaying and positioning errors, and may lead to permanent deformation, instability or fracture. A large gap between actual and calculated deflection suggests overload, loose joints or faults. The jib crane deflection calculator aids troubleshooting and reliable jib crane operation.

Safety factor, k

Rated capacity, Q (N)

Electric hoist weight, Gh (N)

Cantilever beam effective slewing radius, a (mm)

Column effective height, L (mm)

Steel elastic modulus, E (N/mm²)

I-beam specifications

Cantilever beam section inertia, J1 (cm⁴)

Outer diameter of the column steel pipe, D (mm)

Inner diameter of the column steel pipe, d (mm)

Calculated total deflection, δ

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Jib Crane Deflection Calculator Formula

δ = pa³ 3EJ₁ + pa²L EJ₂

p: Safety factor × capacity + electric hoist weight
a: Cantilever beam effective slewing radius
L: Column effective height
E: Steel elastic modulus (typically taken as 2.06 × 10¹¹ Pa)
J₁: Cantilever beam section inertia (I-beam)
J₂: Column section inertia (steel pipe)

J₂ = π 64 (D⁴ − d⁴)

D: Outer diameter of the column steel pipe
d: Inner diameter of the column steel pipe

Notes

The steel elastic modulus is typically taken as 2.06 × 10¹¹ Pa
Safety factor selection: 1.00 for normal static calculation. 1.10-1.15 for start/stop or VFD operation. 1.20-1.30 for faster motion or noticeable impact. Use for preliminary estimation only.
This jib crane deflection calculator already includes common I-beam specifications and their moments of inertia J₁, which reference the structural steel values specified in Annex A of GB/T 706-2016 or ISO 657-1:2026 (the two standards are essentially consistent) and apply to hot-rolled I-beams.
The table below lists other I-beam specifications and their corresponding values for your selection.

Other I-beam Specifications and Section Moment of Inertia
I-beam	Ix / cm⁴	I-beam	Ix / cm⁴
10	245	12	436
12.6	488	14	712
20b	2,500	22b	3,570
24a	4,570	24b	4,800
25a	5,020	27a	6,550
27b	6,870	28b	7,480
30a	8,950	30b	9,400
30c	9,850	32b	11,600
32c	12,200	36a	15,800
36b	16,500	36c	17,300
40a	21,700	40b	22,800
40c	23,900	45a	32,200
45b	33,800	45c	35,300
50a	46,500	50b	48,600
50c	50,600	55a	62,900
55b	65,600	55c	68,400
56a	65,600	56b	68,500
56c	71,400	63a	93,900
63b	98,100	63c	102,000

Source: GB/T 706-2016, Annex A, Table A.1. Ix is the moment of inertia about the x-axis.

Applicable Jib Crane

Free Standing Jib Crane
FEM Standard Jib Crane
Workstation Jib Crane

Contact Details

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