Frame Element Internal Forces Output Conventions

The frame internal forces are:

These internal forces and moments are present at every cross-section along the length of the frame.

For each load pattern and load combination the frame internal forces and moments are computed and reported at each frame output station.

For frame output displayed in a tabular form on the computer screen, printed to a printer or printed to a file, the locations of the output stations are identified by the absolute distance to the station measured from the i-end of the frame.

The sign convention for frame internal forces is illustrated in the figure below. This sign convention can be described by defining the concept of positive and negative faces of an object. Consider a section cut through the object in the 2-3 plane. At this section the positive 1 face is the face whose outward normal (arrow that is perpendicular to the section and pointing away from the section) is in the positive local 1 direction. At this same section the negative 1 face is one whose outward normal is in the negative local 1 direction. The positive 2 and 3 faces are those faces with outward normals in the positive local 2 and 3 directions, respectively, from the neutral axis. Note the following about the frame internal forces: