Bending Stress Calculations

Cairn Energy India PTY Ltd BSPL Project - Barmer to Salaya Pipeline CALCULATION

PROJECT NO.

Allowable Bend Radius 24" Oil Pipeline

52893.03 REF

03-P-2-009

No OF SHEETS

1 of 4 DOCUMENT No

01 REV

OFFICE CODE

PROJECT No

AREA

DIS

TYPE

NUMBER

05

5893

03

P

2

009

PD

JC

PD

BS

CEIL

BY

CHK

ENG

PM

Client

21.05.07 Issued For IDC DATE

DESCRIPTION

Allowable Elastic Bend Radius Calculation

From simple bending theory: R

R=

ED 2σ allow

Note: This calculation considers preliminary principal direction stress only. In the presence of shear or torsion, FEA will be required. External diameter, D, ( mm )

609.6

Wall thickness, T, ( mm )

11.1

Corrosion allowance, ca, ( mm )

0

Milling tolerance, m, ( % )

5

Internal pressure, P, ( Barg )

90

Specified minimum yield stress, SMYS, ( N/mm 2 )

448

Poisson's ratio, p_r, ( - )

0.3

Young's modulus, E, ( N/mm 2 )

206000

Temperature range, DT, ( Degree C )

75

Expansion rate, α, ( m/m/°C)

0.0000117

Combined stress analysis case: Design case

Von Mises equivalent stress Installation

Unrestrained

Restrained

1

0.9

0.9

448.00

403.20

403.20

Hoop stress, ( N/mm 2 )

-

260.14

260.14

Resultant longitudinal stress, ( N/mm 2 )

-

130.07

-102.72

390.21

157.42

Safety factor - must be less than or equal to 1, ( - ) Allowable stress, σallow, ( N/mm 2 )

Sum of Hoop and Longitudinal Tresca equivalent combined stress, ( N/mm 2 )

-

260.14

362.86

Equiv = Von Mises combined stress, ( N/mm 2 )

-

225.29

323.96

0.50

0.72

Ratio of Equivalent to SMYS

2 1 0

Allowable bending stress, ( N/mm 2 )

448.00

177.91

79.24

Allowable bend radius, R, ( m )

140.15

352.92

792.36

19/05/2007

P Doc

Jat Chohan

P Doc

01/05/06

P Doc

GM

P Doc

Date

Drawn

Chkd

Appd

Revised to Suit 800m Bending Radius Issued for internal check

Rev

Cairn Energy

Revisions

Calculated Bend Radius

03-P-2-009 Rev 01 - 24 inch Crude Oil Allowable Bend Radius HDD Pipelay.xls page 2

05 2893 03 P 2 009 (001) 21/05/2007 14:04

Horizontal Directional Drill Calculation Pipe Material Characteristics

R

Pulling stress, from Force/Area

σ pull =

Mat.

Q (Kg/m3)

E (N/mm2)

Polycarb

1200

24100

AL

2690

75000

CS

7830

206000

SS

7987

195000

Titanium

4500

110000

Monel

8800

195000

Copper

8910

124000

From simple bending theory:

fwtot L pull

R =

A

Er

σ allow

External diameter, D, ( mm )

609.6

Wall thickness, T, ( mm )

11.1

Friction Factor in soil, f, ( - )

0.5

Length of pull for crossing, L pull, ( m )

600

Pipe material density, ( kg/m3 )

7850

Specified minimum yield stress, SMYS, ( N/mm2 )

448

Youngs modulus, E, ( N/mm2 )

2 1 0

206000

Radius of pipe, r, ( mm )

304.8

Uncorroded weight of pipe, wtot, ( N/mm )

1.61

Cross sectional area of pipe, A, ( mm2 )

20870.70

Pulling stress, σpull, ( N/mm2 )

23.10

Allowable bend radius stress, σ allow=( 0.9 SMYS ) - σpull, ( N/mm2 )

380.10

Allowable bend radius, R, ( m )

165.19

Revised to 800m allowable bend radius Issued for internal check

Rev

Cairn Energy

Revisions

Horizontal Directional Drill

03-P-2-009 Rev 01 - 24 inch Crude Oil Allowable Bend Radius HDD Pipelay.xls HDD

page 3

19/05/2007

P Doc

Jat Chohan

P Doc

01/05/2007

P Doc

GM

P Doc

Date

Drawn

Chkd

Appd

05 2893 03 P 2 009 (002)

21/05/2007 14:04

Laying analysis Calculation Top of Trench Laying Crain R

Pipeline

Trench floor From simple bending theory: Note: This calculation considers preliminary principal direction stress only. In the prescence of shear or torsion, FEA will be required.

R=

ED 2σ allow

External diameter, D, ( mm )

609.6

Wall thickness, T, ( mm )

11.1

Corrosion allowance, ca, ( mm )

0

Milling tolerance, m, ( % )

5

Specified minimum yield stress, SMYS, ( N/mm2 )

448

Poissons ratio, p_r, ( - )

0.3

Youngs modulus, E, ( N/mm2 )

934812877.3

Imposed load, (N)

125000

CSA, (mm2)

20870.70

Safety factor - must be less than or equal to 1, ( - )

1

Allowable stress, σallow, ( N/mm2 )

448.00

Resultant longitudinal stress, ( N/mm2 )

5.99

Allowable bending stress, ( N/mm2 )

442.01

Allowable bend radius, R, ( m )

142.05

Bending moment, ( Nm )

1355634

Revised to accommodate 800m allowable bend radius Issue for Internal Check

Rev

Cairn Energy

EI R

206000

Moment of inertia I, ( mm4 )

2 1 0

M =

Revisions

Construction Bend Stress

03-P-2-009 Rev 01 - 24 inch Crude Oil Allowable Bend Radius HDD Pipelay.xls

19/05/2007

P Doc

Jat Chohan

P Doc

01/05/07

P Doc

GM

P Doc

Date

Drawn

Chkd

Appd

05 2893 03 P 2 009 (003) 21/05/2007 14:05