***WARNING: THE VALUE OF MOMENT AMPLIFICATION FACTORS KY OR KZ IS GREATER THAN 1.4
FOR MEMBER # XXX FOR LOADCASE- XXX. SECOND-ORDER ELASTIC ANALYSIS MUST BE PERFORMED
AS PER SECTION 4.4.2 of IS800-2007. ALSO, ENSURE THAT THE TYPE OF COMBINATION USED IS
REPEAT LOAD OR REFERENCE LOAD INSTEAD OF THE LOAD COMBINATION SYNTAX EXCEPT FOR
RESPONSE SPECTRUM LOAD CASES.
The warning message has been introduced in STAAD.Pro SS6 build 20.07.11.82. The is related to cl.4.4.2 where it is mentioned that if the Ky and Kz values calculated in cl.9.3.2.2 is greater than 1.4, then a second order analysis is required. For any member for each bending + compression load case, program calculates the Ky and KZ values according to cl.9.3.2 and check it against 1.4. For any load case for which linear analysis has been performed, if the Ky or Kz value is greater than 1.4, program reports the warning message in the output file. A second order analysis (for example, P-Delta analysis in place of perform analysis) is required for those load cases.
Also, for second order analysis Repeat load case is required in place of load combination cases.