Form: Trim/Extend Selected Frames
The Edit menu > Edit Lines > Trim/Extend Frames command can be used to lengthen frame elements that are too short, or shorten frame element that are too long.
Select the frame to be extended or trimmed along with its end points.
Click the Edit menu > Edit Lines > Trim/Extend Frames command to access the Trim/Extend Selected Frames form.
Choose the appropriate option: Trim Frames or Extend Frames.
Click the OK button.
SAP2000 will lengthen or shorten the frame element to the nearest joint/grid intersection.