Effective Length Factor (K)

Enter the Effective Length Factors for the unbraced lengths for bending about the strong (y-axis) and weak (z-axis) axes of the selected members.

From the Main Menu select Design > Common Parameter > Effective Length Factor (K).

First, select the members in the model and enter the following:

Option

Select Add/Replace or Delete.

Add/Replace: Add the newly entered values or update the previously entered values.

Delete: Delete the entered values. Data entry is not required when deleting.
 

 : Apply the entered values to the selected members.

 : Close the entry Dialog Bar.

 Use one of the two following methods for entering data:

<Method 1>

Enter the values directly in the Ky and Kz fields.

<Method 2>

Click and use the K-Factor Input dialog box shown below to enter the values.

Select the effective buckling length factor for the member's strong or weak axis in the K-Factor Input dialog box and click .

Note 1
If the values for Ky and Kz have not been entered, the values Ky = 1.0 and Kz = 1.0 are applied.

Note 2
The program's automatically calculated values can be used as the effective buckling length factors for column members.

In order to automatically calculate the effective buckling length factors, select the Auto Calculate K-Factor option in Definition of Frame.

Follow the procedure below to access Definition of Frame.

From the Main Menu select Design > General Design Parameter > Definition of Frame.

From the Menu tab of the Tree Menu select Design > General Design Parameter > Definition of Frame.

In case when the Factors are not entered:

If 'Auto Calculate K-Factor' is selected in  Definition of Frame., the program automatically calculates Ky and Kz. If 'Auto Calculate K-Factor' is not selected in  Definition of Frame., the program applies a value of 1.0 to Ky and Kz.

If the Factors are entered using this function even when the 'Auto Calculate K-Factor' is selected in Definition of Frame, the Factors entered by the user will be used.

Note 3
If 'Auto Calculate K-Factor' is selected, the effective buckling length factors are calculated simultaneously with the execution of design functions. The calculated values are applied to the relevant column members (elements).

However, if the user specifies the values through the dialog bar, the user-specified values are applied.

The effective buckling length factors obtained by the auto-calculation of the program are produced and marked in the steel member strength verification and the RC column member design results.

If the auto-calculated effective buckling length factors do not represent the true configurations of the members and yield abnormally large values, it is recommended that appropriate design values be directly entered by the user.

Note 4
If the effective buckling length factor is repeatedly entered for the same member, the following procedure is used to set the applicable value :

1. The effective buckling length factor last entered by the user

2. The effective buckling length factor obtained from the auto-calculation option

Note 5
The entered effective buckling length factors can be reviewed in the data table arranged in the order of element numbers. The user may Modify/Add and Delete items in the data table.

Access the data table following the procedure below.

From the Main Menu select Design > General Design Parameter > General Design Tables > Effective Length Factor (K).

From the Tables tab of the Tree Menu select Design Tables > General Design > Effective Length Factor (K).