Mathcad - Spreader Bar Final

CABLE REEL SPREADER BAR DESIGN

1.0 Input Data 1.1 Geometric Parameters 10" Sch60 Pipe Outer Diameter OD  273.05mm Inside Diameter ID  247.65mm Pipe thickness tp  ( OD  ID)  0.5  12.70  mm Pipe Length Considered Lp  2300mm

1.2 Material Properties Yield strength fyp  235MPa Young's Modulus, E  205000MPa kg

Steel density, ρs  7850

3

m Poisson's Ratio , υ  0.3

1.3 Weight Max. Expected Weight Wmax  60.00tonne Add 10% weight contingency Static Hook Load SHL  Wmax  0.1 Wmax  66.00  tonne Dynamic Amplification Factor DAF  1.07  0.05

100 44

 1.15

(DNV-OS-H205)

2.0 Detailed Calculation Forces Upper Sling angle θ  60deg

Lower Sling angle γ  90deg

5% Lower Sling angle variation α  γ  .05  4.5 deg 5% Upper Sling angle variation β  θ  .05  3  deg Load in Upper Sling Fus  Load in Lower Sling Fls 

0.5  DAF  SHL

 43.64  tonne

sin( θ ) 0.5  DAF  SHL cos( α)

 37.91  tonne

2.1 Pipe Compression Check





Upper Sling Compressive Force in Pipe Fusc  Fus  cos( θ  β )  23.77  tonne





Lower Sling Compressive force in pipe Flsc  Fls  cos( γ  α)  0.23 tonne Total Compressive force Fcmp  Fusc  Flsc  24.00  tonne Compressive Stress σcmp 

Fcmp  g 2  2    π  OD    π  ID  4   4  

 22.66  MPa

Allowable Compressive Stress

 OD Inertia Ip   π  64  Ka  1.0

la 

4     π  ID   8.822  107 mm4 64   

4

Lp

r 

1000

Ip 2 2  OD   ID   π    π   4   4   1

Ka  l a r

Fa 

 0.02

Cc 

<

  1   

2  Ka  la      r    f yp 2 2  Cc  

  Ka  l a  3    5 r         8  Cc  3  

URcmp 

σcmp Fa

2  2  π  E   74.034  f  yp  

 0.16

 Ka  l a   

3

   r   3 8  Cc  

< 1 OK

 140.99 MPa

 0.092 m

2.2 Pipe Bending Check Bending Due to Upper and Lower Padeye sling position and sling angle variation.

Distance d b  232mm Weight of Spreader Bar wsb 

2  2    π  OD    π  ID   ρs  g  0.8 kN 4   4  m 

 1.15  w  L 2  sb p Bending Moment Mpb  g   d b Fusc  d b  Flsc     54.16  kN  m 8   Bending Stress σpb 

Mpb  0.5  OD Ip

σpb URpb   0.48 0.75  fyp

 83.816 MPa

< 1 OK

Combined Axial and Bending Check Bending have been considered in one direction URcomb 

σcmp Fa



σpb 0.75  fyp

 0.64

< 1 OK

3.0 Summary of Results Compressive stress ratio URcmp  0.16 Bending stress ratio URpb  0.48 Combined stress ratio URcomb  0.64