asme b31.4 equivalent stress

I created a semplified autopipe model (completely above ground, without soil) to try to verify formulas that it use to calculate the equivalent stress according to ASME B 31.4.

In correspondence of a node in a fully unrestrained pipe, the calculated equivalent stress is exact the same value of hoop stress;(see below values)

Category

Stress

Allowable

 

 

Hoop

229.1

322.68

Sustain

114.69

242.01

Expansion

0

322.68

Eq Tensile

229.1

403.34

in correspondence of a node in a fully restrained pipe, the calculated stress values are listed below

Category

Stress

Allowable

 

 

Hoop

229.1

322.68

Sustain

72.38

242.01

Expansion

207.24

322.68

Eq Tensile

296

403.34

I’m not able to understand which equations it has been used.

Can someone help me?

Another question: in the result grid, is reported a column named “pressure”, what means?

Thanks in advanced.

Regards

  • Hi Franco,

    For fully unrestrained pipe above ground, it is sensible that you may see equivalent tensile stress equal to Hoop stress provided there is no torsional stress. Please check the topic "Reference Information > Code Compliance Calculations > ASME B31.4 (2006) > Equivalent Tensile Stress" for details. Also see attached zip file containing a PDF having more details on Equivalent Tensile Stress calculations.

    For the second question, the pressure column represents the longitudinal pressure stress. Please see the following from the online help. Hope this helps.

    B314_Eq_Tens.zip

    Regards,

    Bilal Shah

    MISSING RESOURCE: VerifiedBy Luke Andrew