Form: Frame Property/Stiffness Modification Factor
Modification factors can be defined as part of frame section properties and assigned directly to frame objects. Note that when modification factors are assigned directly to a frames that also has modification factors defined as part of its frame section properties, the two factors are multiplied. Therefore, it is intended that modification factors be specified using a frame section property definition or a frameassignment, not both.
The definition of modification factors as part of frame section properties allows application of modification factors whenever a particular property definition is used.
The line objects assignment allows application of modification factors on a "line-object-by-line-object" basis (although multiple objects can be selected). This may be needed to incorporate the effect of cracking of sections or the enhancement in a particular property of the section because of the presence of other members that may, for some reason, not have been modeled. SAP2000 allows you to change these properties for frame objects.
Note that the modification factors affect only the analysis properties. They do not affect the design properties. The SAP2000 default for all modification factors is 1.
Specify modification factors as part of the section properties as follows:
Click the Define menu > Frame Sections command to access the Frame Properties form.
If a new frame section is being defined, use the Choose Property Type to Add drop-down lists to import or add the frame section and click the Add New Property button.
Note: Modification factors cannot be assigned to Auto Select Section lists, which usually consist of multiple sections. If you select an Auto Select Section list from the list of names in the Properties area of the form, the Auto Selection Sections form appears. Close that form by clicking the Cancel button to return to the Frame Properties form and choose an individual section before continuing.
If an existing frame section definition is being revised, highlight the name of the frame section in the Find This Property display list and click the Modify/Show button.
A form specific to the type of section will appear. Click the Set Modifiers button on the form to access the Frame Property/Stiffness Modification Factors form.
Enter the required values for the modification factors by typing the values in the edit boxes for the individual factors; then click the OK button.
Specify modification factors on an frame-by-frame basis as follows:
Select the frame(s) to be assigned property modification factors.
Click the Assign menu > Frame > Property Modifiers command to access the Frame Property/Stiffness Modification Factors form.
On the Frame Property/Stiffness Modification Factors form, enter the desired value for the modification factors by typing the value in the edit box for the individual factors
Click the OK button.
See Also