A few enhancements/modifications regarding the calculation of the effective length factor in IS, ACI, and NSCP design codes have been done in the 11.6 and earlier versions of RCDC.

If the user opens the old version RCDC file to the 11.6 version RCDC will show a message to restore default values of the effective length factor. This is applicable to the column module of IS, ACI, and NSCP codes.

 

This is to inform the user that values need to be corrected for effective length factor to get the correct design. If the user has used the program to calculate the effective length factor, then it is recommended to update the effective length factor.

defect / enhancement done for effective length calculations are listed below,

 In the 11.6 release, an issue related to the calculation of the effective length factor when no beams are present at that level has been resolved. The issue was in ACI and NSCP codes.

The effective length of the column is calculated based on the Ψ factor. Ψ is the ratio of the column stiffness to the beam stiffness in a plane at one end of the column.

Issue:

In case there are no beams present at a particular level, the value of Ψ should be considered as 1. In the recent version of RCDC, the wrong value of Ψ is used to calculate the effective length factor.

Solution:

The correct value of Ψ is used and presented for the calculation of the effective length factor if beams are not present at that level.

 

  In the 11.5 release, the issue related to the calculation of the factor ψ which depends on the type of frame was resolved. This issue was specific to ACI and NSCP design codes.

 The effective length factor of the column is based on the type of frame (Sway or Non-sway) and ψ factor which is the ratio of column stiffness to beam stiffness in a plane at one end of the column. The effective length factor calculated for factor ψ was wrong in the earlier version.

Solution:

Now the correct effective length factor is calculated for factor ψ.

In the 11.5 release, Enhancement related to calculation of Effective Length calculation when beams are non-orthogonal in Plan

In case of beams are not orthogonal to the Major or Minor axis of the column, the stiffness of those beams is resolved along the column axis.

 In the 11.4 release, the issue of reading story shear for the parametric surfaces was resolved in this release. This issue was resolved for IS, ACI, and NSCP design codes.

 The story shear computation for each story of the parametric surface modeled in the structure is enhanced. In the earlier release, the story shear values were wrongly computed for parametric surfaces. Now, the story shear along the major and minor directions of the parametric surface is computed considering all possible cases of modeling parametric surface in STAAD.