Missing Mass Combination Method (SRSS/ABS) - CAESAR II - Help

CAESAR II Users Guide (2019 Service Pack 1)

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English
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CAESAR II
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CAESAR II Version
11.0 (2019)

(Available for: Spectrum)

Specifies the method for combining the missing mass/force correction components with the modal (dynamic) results. Select SRSS for a square root of the sum of the squares combination method. Select ABS for an absolute combination method.

Research suggests that the modal and rigid portions of the response are statistically independent, so SRSS is usually most accurate. ABS provides a more conservative result, based upon the assumption that the modal maxima occur simultaneously with the maximum ground acceleration. Missing mass components are combined following the modal combination. For more information, see Include Missing Mass Components.

Even though missing mass components may be included during time history analyses, all time history combinations are done algebraically (in-phase), so this parameter has no effect on time history results.