ASME VIII, Section UG-27

[Mahmoudem2]

why in the ASME code section VIII Div.1 , at the UG-27 when the code represent the forms equation of the thickness of the shell..
.. the code present two equation ( longitudinal , circumferential ) and we take the biggest value , but we now that the allawable stress for the circumferential is bigger than the longitudinal stress .....!!

so ,we the code put the two equations ?

 

[SnTMan]

Mahmoudem2, longitudinal stress is of interest for seamless sections, and for evaluating other applied loadings.

Regards,

Mike

 

[metengr]

ASME Section VIII, Div 1 is "design by rule". This means primary stress in a shell is evaluated in two directions (hoop and circumferential). This is the reason for the two equations and to use the most conservative approach.

 

[jamesl]

When the longitudinal stress from internal pressure is combined with stress from wind or seismic loading, the total stress in longitudinal direction could govern the shell thickness. If you designed many tall columns, you might run into such cases once a while.