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Input Data: Pipeline Diameter D = 168.3 mm Design Pressure P = 23.0 Mpa Installation Temperature T i = 21 Deg C Max. Design Temperature (U/G) T2 = 85 Deg C Min. Design Temperature (U/G) T1 = 4 Deg C SMYS of linepipe material S = 241 MPa Youngs modulus of pipe E = 207000 MPa Steel expansion coefficient α = 0.0000116 mm /m / o C Poisson/s ratio = 0.3 Corrosion Allowance CA = 3.0 mm Pipeline Deisgn factor f = 0.72 Joint efficiency factor e = 1.0 Temperature derating factor T = 1 Min. Required Thickness(incl. CA) t min = 11.15 mm Selected wall thickness (incl. CA) t s = 14.27 mm Selected wall thickness without CA t = 11.27 mm Restrained Pipe Stress Calculation Hoop stress S h = PD / 2t S h = 171.73469 MPa Longitudinal Stress due to Internal Pessure SP = Sh SP = 51.520408 MPa Thermal stress (Compressive) S tc = Eα (Ti T2) = 153.6768 MPa Thermal stress (Tensile) S tt = Eα (Ti T1) = 40.8204 MPa Longitudi. stress (fully restrained) S LC = (S h P)+Eα (T2Ti) = 109.06 Mpa S Lt = S h P)+Eα (T1Ti) = 85.44 Mpa Allowable equivalent stress S AE = 0.9 x S x T S AE = 216.9 MPa Bending Stress based on Von mises Equivalent stress Criteria S eq = (S L 2 S L S H +S H 2 ) 0.9ST (As per ASME B 31.8/ASME B 31.4) S L = {S H ±S H 2 4(S H 2 (0.9ST) 2 )]}/2 S L1 = 243.75 Mpa S L2 = 72.01 Mpa Max. value of Net Longitudinal Stress, S L = 72.01 Mpa Allowable Bending Stress values S B1 = S L S Lc SB3 352.80 S B1 = 37.04 Mpa S B2 = S L S Lt SB4 158.31 S B2 = 157.45 Mpa Maximum Allowable Bending Stress |S B | = 37.044018 Mpa Minimum Allowable Elastic bend radius Allowable Bending Stress S B = 37.04 Mpa Min. Allowable Bending Radius R = ED/2S B = 470.23 m = 2794 D Value > 0.9ST Value<=0.9ST

Elastic Bending Radius Calculation of PIPELINES

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Page 1: Elastic Bending Radius Calculation of PIPELINES

Input Data:Pipeline Diameter D = 168.3 mmDesign Pressure P = 23.0 Mpa

Installation Temperature Ti = 21 Deg C

Max. Design Temperature (U/G) T2 = 85 Deg CMin. Design Temperature (U/G) T1 = 4 Deg CSMYS of linepipe material S = 241 MPaYoungs modulus of pipe E = 207000 MPa

Steel expansion co‐efficient α = 0.0000116 mm /m / oCPoisson/s ratio = 0.3Corrosion Allowance CA = 3.0 mmPipeline Deisgn factor f = 0.72Joint efficiency factor e = 1.0Temperature derating factor T = 1Min. Required Thickness(incl. CA) tmin = 11.15 mm

Selected wall thickness (incl. CA) ts = 14.27 mm

Selected wall thickness without CA t = 11.27 mm

Restrained Pipe Stress Calculation 

Hoop stress Sh = PD / 2t

Sh = 171.73469 MPa

Longitudinal Stress due to Internal Pessure SP = ShSP = 51.520408 MPa

Thermal stress (Compressive) Stc = Eα (Ti ‐ T2) = ‐153.6768 MPa

Thermal stress (Tensile) Stt = Eα (Ti ‐ T1) = 40.8204 MPa

Longitudi. stress (fully restrained) SLC =  (Sh‐P)+Eα (T2‐ Ti) = ‐109.06 Mpa

SLt = Sh‐P)+Eα (T1‐ Ti) = 85.44 Mpa

Allowable equivalent stress SAE = 0.9 x S x T

SAE = 216.9 MPa

Bending Stress based on Von mises Equivalent stress Criteria

Seq= (SL2‐SLSH+SH

2) 0.9ST (As per ASME B 31.8/ASME B 31.4)

SL = {SH±SH2‐4(SH

2‐(0.9ST)2)]}/2

SL1 = 243.75 MpaSL2 = ‐72.01 Mpa

Max. value of Net Longitudinal Stress, SL  = ‐72.01 Mpa

Allowable Bending Stress values 

SB1 = SL‐SLc SB3 352.80

SB1 = 37.04 Mpa

SB2 = SL‐SLt SB4 158.31

SB2 = ‐157.45 Mpa

Maximum Allowable Bending Stress  |SB| = 37.044018 Mpa

Minimum Allowable Elastic bend radiusAllowable Bending Stress  SB = 37.04 Mpa

Min. Allowable Bending Radius R = ED/2SB= 470.23 m = 2794 D

Value > 0.9ST

Value<=0.9ST