HDD Calculation

(1)

20

600

720

10

52.18

125.66

247.17

125.66

52.18

602.86 DESIGN DATA

Pipeline Diameter

D

36 inch

914.4 mm

3 ft

thickness (min)

t

15.9 mm

18.3 mm (D/t should be < 60)

0.626 in

Pipeline Material Grade

X60

SMYS of Pipeline

S

415 Mpa

60190.77

Steel Density

7850

Water Density

1000

Soil Density

1800

112.37 Mud Density

1437.8

89.76 Drilling Fluid Density

11 lb/gal

1318.09

Soil friction Angle



30 degree

Poisson Ratio for Steel



0.3 Modulus of Elasticity

E

207000 Mpa

30022866

Installation Temperature

T1

13 degC

Operating Temperature

T2

65 degC

Steel Coefficient Thermal



0.0000117 mm/mm/°C

Friction Factor of Soil

0.5 Assumed

Fluid (mud) Drag Coefficient

0.05 344.73785 Pa

Test Pressue

137.1 Bar

(Test pressure =95 % SMYS)

Design Pressure

P

63.5 Bar

921 CALCULATIONS

Pipe Cross Sectional Area

656692.89

0.657 Steel Cross Sectional Area

44881.26

0.045 Uncorroded weight of Pipe

352.32 kg/m

Displace Mud Weight

944.20 kg/m

Effective (submerged) weigth of pipe

-591.89 kg/m

Wsub = Ws - Wmud

Earth Pressure Coefficient

K

0.577 Arching Factor



0.148 L

_depth

L

_crossing

R

_arc1

R

_arc2



_in





L

₁

L

_arc1

L

₂

L

_arc2

L

₃

L

_tot

lb/in

2



s

kg/m

3



w

kg/m

3

kg/m

3

_lb/ft

3

kg/m

3

_lb/ft

3



d

Kg/m

3

lb/in

2



s



mud

lb/in

2

P

T

lb/in

2

mm

2

_m

2

A

s

mm

2

m

2

W

_s

W

mud

W

_sub

(2)

Page 2 of 5

INSTALLATION STRESSES

Pulling Loads

Frcition Force

15208.75 kg

Fluid Drag

51678.38 kg

Pipe Weight (longitudinal direction)

8555.98 kg

T1

58331.14 kg

Frcition Force

37189.31 kg

Fluid Drag

124447.14 kg

Pipe Weight (longitudinal direction)

0.00 kg

219967.59 kg

Frcition Force

73146.80 kg

Fluid Drag

244772.22 kg

Pipe Weight (longitudinal direction)

0.00 kg

T2

537886.61 kg

Frcition Force

37189.31 kg

Fluid Drag

124447.14 kg

Pipe Weight (longitudinal direction)

118652.20 kg

Pulling load at end of Larc2

818175.26 kg

Frcition Force

15208.75 kg

Fluid Drag

51678.38 kg

Pipe Weight (longitudinal direction)

8555.98 kg

Pulling load at end of L1

T3

893618.37 kg

Straight Section L

₁

|F

f1

|

|F

_f1

| = W

_sub

x L

₁

cos (



in

) x



s

F

_D1

F

_D1

=



x D x L

₁

X



mud

W

p1

W

_p1

= W

_sub

x L

₁

sin (



in

)

Pulling load at end of L

1

T1 = |F

_f1

| + F

_D1

- W

_p1

Curve Section L

_arc1

|F

farc1

|



considered 0deg for conservatism

|F

_farc1

| = W

_sub

x L

_arc1

cos (



) x



s

F

Darc1

F

_Darc1

=



x D x L

_arc1

X



mud

W

parc1



considered 0deg for conservatism

W

_parc1

= W

_sub

x L

_arc1

sin (



)

Pulling load at end of L

arc1

T

arc1

T

_arc1

= T1 + |F

_farc1

| + F

_Darc1

- W

_parc1

Straight Section L

₂

|F

_f2

|

_

= 0deg for straight section

|F

f2

| = W

sub

x L

2

cos (



) x

s

F

_D2

F

D2

=



x D x L

2

X



mud

W

_p2

_

= 0deg for straight section

W

p2

= W

sub

x L

2

sin (



)

Pulling load at end of L

₁

T2 = T

arc1

+ |F

f2

| + F

D2

- W

p2

Curve Section L

_arc2

|F

_farc2

|

_

considered 0deg for conservatism

|F

_farc2

| = W

_sub

x L

_arc2

cos (



) x



s

F

Darc2

F

_Darc2

=



x D x L

_arc2

X



mud

W

_parc2

_

considered 90deg for conservatism

W

_parc2

= W

_sub

x L

_arc2

sin (



)

T

_arc2

T

arc2

= T

2

+ |F

farc2

| + F

Darc2

+ W

parc2

Straight Section L

₃

|F

f3

|

|F

_f3

| = W

_sub

x L

₃

cos (F

_out

) x



s

F

D3

F

_D3

=



x D x L

₃

X



mud

W

p1

W

_p3

= Ws

_ub

x L

₃

sin (



out

)

(3)

Pulling Loads =

893618.37 kg

(4)

Page 4 of 5

Tensile Stress

Tensile stress

19.91 MPa

Allowable Tensile Stress :

90% of SMYS

373.50 MPa

Condition :

OK

Bending Stress

131.45 MPa

Allowable Bending Stress

D/t

57.51 for D/t <

24.921 Fb =

45143.08

311.251 MPa

24.92 < for D/t <

49.842 Fb =

38485.01

265.345 MPa

for D/t >

49.842 Fb =

39312.27

271.049 MPa

265.34 MPa

Condition :

OK

Hoop (External Pressure) Stress

External Pressure

60 kPa

(Ranging from 30 kPa to 60 kPa)

0.06 MPa

Hoop Stress due to External Pressure

1.73 MPa

Elastic Hoop Buckling Stress

0194318 psi

6E+008 MPa

Critical Hoop Buckling Stress

87380194318 psi

33104.9

15728462063 psi

33104.92

96305.2

68565.10 psi

96305.23

373183

60190.77 psi

373182.77

Critical Hoop Buckling Stress :

15728462063 psi =

108443971.09 MPa

Allowable hoop stress = 67% of Critical Hoop Buckling Stress =

72657460.63 MPa

Condition :

OK

Combined Installation Stress

Combined Installation Stress should satisfy the following condition:

Condition :

OK

Condition :

OK

0.4533

0.0000



t



t

= Pulling Loads / Steel Area



b

b

= E D / 2R

lb/in

2

lb/in

2

lb/in

2

Allowable Bending Stress (S

_b

) :

P

_ext



hext

F

he

F

_hc

F

_he

<

F

_hc

< F

_he

<

F

_hc

< F

_he

<

F

_hc

< F

_he



t

/ 0.9S +



b

/ S

b

< 1

A

2

_{+ B}

2

_{+ 2}

_

_{|A|B < 1}

A = [ (



t

+



b

- 0.5



hext

) / 1.25] / S

B = 1.5



hext

/ F

hc

(5)

OPERATING STRESSES

Hoop Stress due to Internal Pressure

182.59 MPa

Bending Stress

131.45 MPa

Thermal Expansion

-125.94 MPa

External Pressure

Pe

52108.43 Pa

0.0521 MPa

7.56 psi

Allowable Operating Stress

Total circumferential stress

180.87 MPa

Net Logitudinal Stress

59.77 MPa

CRITERIA :

373.50 MPa

Hence :

OK

Combined stress

(1)

121.10 MPa

(2)

159.61 MPa

CRITERIA :

373.50 MPa

Hence :

OK



h



h

= P D / 2t

b



b

= E D / 2R

th



th

= E



(T1-T2)



C



C

=



h

-



hext



L



L

=



b

+



th

+



C





L

≤ 0.9 S =

S

_E1

= |



C

-



L

|

s

E1

S

_E2

= (



C2

+



L2

-



C



L

)

1/2

s

E2

Combined stress, S

E

= Max (S

E1

, S

E2

)

s

E