Saddle 1

Page

L1

L4

g

g

a

tw

a tr 

H1

tb H3

H

x

x

Ws L3

H2

y

ts

y

L4 (Typ.)

L2

B Lb

Vessel Outside Diameter W rapper Plate Thickness Saddle Included Angle Wrapper Plate Included Angle W rapper Plate W idth Height from Saddle base to Vessel CL Saddle Stiffener Thickness W eb Plate Thickness Saddle W idth Base Plate W idth Distance from Saddle CL to outer Anchor Bolt CL Base Plate Thickness Base Plate Length Distance from Outer Stiffener CL to Vessel CL Distance from CL of web to CL of Anchor Bolt Distance from edge of W eb to edge of Base

Do tr 2 a 2 (g + a) Wr H ts tw Ws Wb B tb Lb L2 L3 L4

= = = = = = = = = = = = = = = =

1219 9.53 120 132 250 1390 9 9 150 250 450 15.875 1125 350 60 25

mm mm Deg Deg mm mm mm mm mm mm mm mm mm mm mm mm

Height from Saddle base to outer stiffener H - ((Do/2) + tr)) x Cos

H1

=

1080

mm

Outer Stiffener Height H - ((Do/2 + tr)^2 - L2^2)^0.5 - tb

H2

=

864

mm

Inner Stiffener Height H - (Do/2 + tr) - tb

H3

=

755

mm

Ov erall Length of Saddle 2 x Sin a x (Do /2 + tw)

L1

=

1072

mm

Cross Sectional Area of Saddle Stiffeners 3 x (ts x (Ws-tw) + (tw x L1)

As

=

#REF!

mm^2

Minimum Saddle Section Modulus (3 x ts x (Ws^2/6)) + (Lb - (3 x ts x (tw^2/6))

Z xx

=

#REF!

mm^3

Minimum Saddle Section Modulus (tw x (Lb^2/6)) + (5 x (Ws - tw)/L x (tw^2/6))

Z yy

=

#REF!

mm^3

Base Plate Section Modulus Wb x tb^2/6

Zb

=

10501

mm^3

(A 516M Gr.485)

(A 36M OR EQ.) (A 36M OR EQ.)

(A 36M OR EQ.)

Wb

Page

STRESSES IN SADDLE WRAPPER PLATE Ref BS5276 Pt 2 Wrapper Plate Inside Radius

Rr

=

609.53

mm

b

=

120

Deg

R

=

#REF!

N

P

=

#REF!

N/mm width

q

=

#REF!

N/mm^2

Ref Roark & Young Table 26 Case 9a for

a b a/b b1

= = = =

341.0 70.5 4.837 0.718

mm mm

Maximum Bending Stress in Wrapper Plate b1 x q x b^2/tr^2

fbr

=

#REF!

N/mm^2

#REF!

Shear Stress in Saddle Wrapper Plate P/(2 x tr)

fsr

=

#REF!

N/mm^2

#REF!

Bearing Stress in Wrapper Plate P/tw

fpr

=

#REF!

N/mm^2

#REF!

 Angle b 180 - a Maximum Reaction Load at Saddle (FPSO Motion)

=

Consider a 1mm wide strip of Wrapper Plate Load/unit Width R/Rr x (1 + Cosb

)/(( 3.14159 b-

) + (bCos

)x b ( Sin

Load per unit area of Wrapper Plate P/Wr 

))

STRESSES IN BASE PLATE (Compressive Loading)  Assume that the saddle is sufficiently rigid to distribute the compressive load uniformly over the total base plate area. Consider a 1mm wide strip of Base Plate Load per unit width of Base Plate R/L

P

=

#REF!

N/mm width

Load per unit area P/Wb

q

=

#REF!

MPa

Ref Roark & Young Table 26 Case 10a for

a b a/b b1

= = = =

341.0 70.5 4.837 2.105

mm mm

Maximum Bending Stress in Base Plate b1 x q x b^2/tb^2

fbb

=

#REF!

N/mm^2

#REF!

Shear Stress in Saddle Base Plate P/(2 x tb)

fsr

=

#REF!

N/mm^2

#REF!

Bearing Stress in Base Plate P/tw

fpr

=

#REF!

N/mm^2

#REF!

2.094

Rads

Page

Lateral Tensile Stress in Saddle Horizontal Load in Saddle is given by

Fh

=

W x K9

2a

=

120

Deg

Hence

K9

=

0.88

(Ref BS5500 App G.3.3.2.6)

Therefore

Fh

=

#REF!

N

Maximum Saddle Height that can resist Fh Do/6

H4

=

203

 Actual Height used for calculation of Tensile Stress Min. of H4 or H3-tb

H5

=

203

 Area resisting Fh H5 x tw +Wr x tr 

Ash

=

1829

mm^2

Tensile Stress in Saddle Fh/Ash

fts

=

#REF!

N/mm^2

H1

=

1065

mm

tw(min)

=

5.91

mm

Saddle Included Angle

#REF!

WEB PLATE Maximum Height of Web and Outer Stiffeners Ref. BS 449 Clause 27f for Grade 43 steel Minimum permissible thickness of Web H1//180

OK

Note :  A 516M Gr.485

A 36M OR EQ.

Min. Yield Stress Min. Allowable Stress

Sy Sa

= =

262.00 137.89

N/mm^2 N/mm^2

248.22 114.46

N/mm^2 N/mm^2

 Allowable Bending Stress  Allowable Compressive Stress  Allowable Shear Stress  Allowable Bearing Stress  Allowable Tensile Stress

Sb = Sc = Ss = Sbr = St =

172.92 157.20 110.31 220.62 157.20

N/mm^2 N/mm^2 N/mm^2 N/mm^2 N/mm^2

163.83 148.93 91.57 183.13 148.93

N/mm^2 N/mm^2 N/mm^2 N/mm^2 N/mm^2