SIF Multiplier for Sustained Stress Index - CAESAR II - Help

CAESAR II Users Guide

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CAESAR II
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CAESAR II Version
12

Modifies the stress index for sustained loads and occasional loads. The default setting is 0.0000, which indicates that the software uses whatever the currently active piping code recommends for the SIF/Index multiplier. For example, if this configuration setting is set to 0.000 and you select B31.3 or B31.3 Chapter IX, the code defines the SIF multiplier as 0.7500.

With the release of CAESAR II 2014 and the implementation of B31.3 2012, the internal interpretation of this existing configuration setting was changed. B31.3 2012 defines the SIF multiplier value as 0.75. Other codes similar to B31.3 do not address this value. The default value of this configuration setting was changed to 0.0000. This change enables CAESAR II to internally set the multiplier to 0.7500 for B31.3 and to 1.0000 for other similar codes. The following table summarizes these settings.

Option




Configuration
SIF Multiplier Setting



Sustained Moment Multiplier (I)

B31.3, B31.3 Ch IX, B31.4,
& B31.4 Ch XI Codes

Codes similar to B31.3
(such as: JPI, B31.5)

Option 1
(default)

0.0000

I = 0.75i

I = i (similar to Option 4)

Option 2

0.0001

I = 1.0

I = 1.0

Option 3

0.7500

I = 0.75i

I = 0.75i

Option 4

1.0000

I = i

I = i

This change does not affect all piping codes.

The following interpretations apply to B31.3 code prior to the 2010 Edition, so they are only applicable if you need to analyze older jobs to the older code addenda:

  • B31.3 Interpretation 1-34 (February 23, 1981) File: 1470-1 states that for sustained and occasional loads, you can use a SIF of 0.75i, but not less than 1.0. To comply with this interpretation (1-34), type 0.7500.

  • B31.3 Interpretation 6-03 (December 14, 1987) File B31-87-022 permits you to ignore the stress intensification for sustained and occasional loads. To comply with this interpretation (6-03), type 0.0001.