When you select Effective Properties from the Compute menu, a dialog window is displayed to enter internal forces. These forces are used in calculating the effective section properties. The greater the compression stress, the less effective the section becomes.

After you enter the appropriate values, press the OK button and the corresponding effective section properties output will be displayed. These calculations use the AISI provisions for servicability determination. For the Direct Strength Method (DSM) both local buckling and distortional buckling are evaluated in determining the effective section properties.

P/Pn | Ratio of axial force to nominal axial strength based on a fully braced condition. A positive value indicates compression, and the ratio is based on the nominal compression strength. A negative value indicates tension, and the ratio is based on the nominal tension strength. |

Mx/Mxn | Ratio of applied moment about the X axis to the nominal moment strength based on a fully braced condition. A positive value indicates compression above the X axis. |

My/Myn | Ratio of applied moment about the Y axis to the nominal moment strength based on a fully braced condition. A positive value indicates compression to the right of the Y axis. |

P | Axial force applied to the section. Positive loads are compression and negative loads are tension. |

Mx | Moment about the X axis applied to the section. Positive moments produce compression above the X axis. |

My | Moment about the Y axis applied to the section. Positive moments produce compression to the right of the Y axis. |