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Steel purlin PMM ratio not satisfied.

This message is created by specifying the element name and floor on which it is located at the beginning of the report.

For example,

PE01 BASE STORY PMM ratio not satisfied.

In steel element design, the design ratio under the combined axial force and biaxial bending (PMM ratio) is made by the CYTHYE 2016 (GKT & YDKT), AISC 360-16 (ASD & LRFD) or EN 1993-1-1. According to AISC 360-16, axial force and biaxial bending interaction equations are calculated below.

  • The PMM ratio value should be less than 1,00.

Possible Solutions:

  • Laterally unbraced length can be reduced by defining tension rods in steel purlins.

  • Roof braces (horizontal braces) and purlins can be removed from the analysis system, provided that stability elements are defined. This option allows the calculation of the design ratio based on biaxial bending, ignoring the axial pressure forces on the purlins. Inclusion of purlins in the analysis system

  • After the purlins are defined, any undivided purlins from the support beams can be divided from the beams supported using the divide-combine all Intersections command.

  • Purlin spacing can be reduced.

  • Steel purlin cross-section can be enlarged.

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