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Lifting Lug Calculation

This document summarizes the design calculations for lifting lugs to lift an object weighing 3500 kg. It includes inputs like material properties, lug dimensions, load weight. Stress calculations are shown to check the lug and welds will not exceed allowable stresses. The calculations conclude that 4 lugs of size 100mm x 180mm x 10mm thickness are adequate to safely lift the load within a factor of safety of 1.5. Standards used for the design are listed.

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Andy Chan
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7K views5 pages

Lifting Lug Calculation

This document summarizes the design calculations for lifting lugs to lift an object weighing 3500 kg. It includes inputs like material properties, lug dimensions, load weight. Stress calculations are shown to check the lug and welds will not exceed allowable stresses. The calculations conclude that 4 lugs of size 100mm x 180mm x 10mm thickness are adequate to safely lift the load within a factor of safety of 1.5. Standards used for the design are listed.

Uploaded by

Andy Chan
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as XLSX, PDF, TXT or read online on Scribd
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CALCULATION SHEET

PROJECT : HKBU Link Bridge


DATE: 9/24/2021
SUBJECT: Lifting Lug Design Calculation
Input
Page
R

D
H

h
T
B

Lw

Lifting Lug Material: BS EN 10025 Part 4 Sy = 355 N/mm2

Thickness of Lug: T= 10 mm
Width of Lug: B= 100 mm
Height of Lug: H= 180 mm
Lug Outer Radius: R= 50 mm
Diameter of Lug: D= 50 mm
Height to hole Center: h= 130 mm
Fillet Weld Leg: Lw = 10 mm
Fillet Weld Throat: S= 7.07 mm
Weight of the lifting object: We = 3500 Kg
Factor of Safety: Fc = 1.5
Design Weight: Wd = Fc x We Wd = 5250 kg
Number of lugs: N= 4
Design Weight per lug: W = Wd / N W= 1312.5 kg
(In Newton W x 9.8 m/s2) 12862.5 N

Lifting Angle: β= 45 o deg


Tension in Sling Ft = W / Sin β Ft = 18190 N
Forces: Fx = Ft x Cos β Fx = 12862.5 N
Fy = Ft x Sin β Fy = 12862.5 N
CALCULATION SHEET
PROJECT : HKBU Link Bridge
DATE: 9/24/2021
SUBJECT: Lifting Lug Design Calculation
Check
Page 1.0 Check Lifting Lug Stress

Shear Stress of Lug at Eye: Fse = Ft / [2 x (R-D / 2) x T] Fse = 36.3806 N/mm2

Strength of lug to resist shear: Fsg = Sy x 0.4 Fsg = 142 N/mm2

Since strength of lug to resist shear is greater than shear stress at eye, therefore OK!

Tensile Stress of Lug at Eye:Fte = Fy / [2 x (R-D) x T] Fte = 25.725 N/mm2

Strength of lug to resist tensile: Ftg = Sy x 0.6 Ftg = 213 N/mm2

Since strength of lug to resist tensile is greater than tensile stress at eye, therefore OK!

Bending stress of lug at base:

Section modulus at base of lug: Z = B2 x T / 6 Z= 16667 mm3

Area at base of lug: A = B x T A= 1000 mm2

Bending Stress at lug base: Sb = Fx x h / Z + Fy / A Sb = 113.19 N/mm2

Since strength of lug to resist bending is greater than Sb, therefore OK!

2.0 Check Weld at Base of Lug

Weld length at base of lug: L = [(T + B) * 2] - (2*Lw) L= 200 mm

Section modulus of weld: Zw = S x (B)2 / 3 Zw = 23567 mm3

Section Area of weld: Aw = S x 2 x B Aw = 1414 mm2

Stress of weld:
From force Fx,
Bending S1 = Fx x h / Zw S1 = 70.953 N/mm2
Shear S2 = Fx / Aw S2 = 9.09653 N/mm2
Combined: Sb = √(S12+S22) Sb = 71.5337 N/mm2

Since strength of weld (220 N/mm2) is greater than stress from Fx, therefore OK!
CALCULATION SHEET
PROJECT : HKBU Link Bridge
DATE: 9/24/2021
SUBJECT: Lifting Lug Design Calculation
Check
Page From Force Fy,
Shear S3 = Fy / Aw S3 = 9.09653 N/mm2

Since strength of weld (220 N/mm2) is greater than stress from Fy, therefore OK!

Max. combined stress due to Fx + Fy,

Smax = √(S1 + S3)^2 + S2^2) Smax = 80.5647 N/mm2

Since strength of weld (220 N/mm2) is greater than stress from Fy, therefore OK!

3.0 Conclusion

From the above design calculation, it is concluded that 4 number


of lifting lug(s) in size:

100 mm x 180 mm x 10 mm

is adequate to lift the object in weight 3500 kg or


34.3 kN

4.0 Design Standard or Code Used

1.) Code of Practice For Structural Use of Steel 2011


2.) BS EN 10025 Part 4

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