B31.4 Chapter IX - CAESAR II - Help

CAESAR II Users Guide

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CAESAR II Version
12

Chapter IX presents the offshore requirements of B31.4. For more information, see B31.4 and B31.4 Chapter XI.

Calculate Stress Intensification Factors (SIFs), flexibility factors, and section moduli

Calculate all SIFs, flexibility factors, and section moduli exactly as stated in the standard B31.4 code.

Calculate stress using B31.4 Chapter IX

Use the uncorroded wall thickness to make stress calculations.

Calculate load cases using B31.4 Chapter IX

There is no provision for a code check for the expansion load case, so no expansion cases are generated under this code. Operating, sustained, or occasional load cases are treated identically. Do three stress calculations for these load cases, each with a different allowable limit. The Stress Report displays the calculation causing the highest percent of allowable along with its specific allowable. These three stress checks are:

Hoop Stress: Sh £ F1 Sy

Longitudinal Stress: |SL| £ 0.8 Sy

Equivalent Stress: Se £ 0.9 Sy

Where:

Sh = (Pi – Pe) D / 2t, when D/t >= 20

Sh = (Pi – Pe) (D-t) / 2t, when D/t < 20

Pi = Internal Pressure

Pe = External Pressure

D = Outer Diameter

t = Wall Thickness

F1 = Hoop Stress Design Factor 0.60 or 0.72, see Table A402.3.5(a) of the B31.4 Code

Sy = Specified Minimum Yield Strength

SL = Sa + Sb or Sa - Sb, whichever results in greater stress value

Sa = Axial Stress Positive Tensile and Negative Compressive

Sb = Bending Stress

Se = 2[((SL - Sh)/2)2 + St2]1/2

St = Torsional Stress