Results - Member Forces
Following a successful analysis of one or more stories you can select to display the Member Forces and Beam/Column force diagram from each story's analysis. These results can be used to independently verify the results of the analysis and duplicate the calculated beam and column design forces. Forces and diagrams are only displayed on members that have significant forces for the selected load case. Click Apply to have the current selections displayed on the screen.
The display options selected here are only visible on the screen while this dialog box is displayed. The dialog box can be moved and the screen printed and model manipulated (zoom etc) while this window is displayed.
Click Apply to have the current selections displayed on the screen.
| Setting | Description |
|---|---|
| Story | Select the Story for which to display member forces from the analysis. When a story is selected all the analyzed load cases for that story will be available for selection in the Load Case drop-down. When you select Apply, only the members of the structure that were part of the analysis of this story will be displayed |
| Load Case | Select the load case for which to display member forces. Refer to the Analysis Criteria (see Section 2.5.2) for more information on how load cases are generated. Click Apply to have the member forces displayed on the screen for the current load case. The beams that are loaded in the selected load case are highlighted. If no beams are highlighted then the selected load case is one in which only the columns are loaded (loads from story above or user applied column point loads). Load Cases are labeled according to their type (Dead Load = DL, Live Load Reducible = LLred, Live Load Unreducible and Partition = LLunred, Live Load Storage = LLstor, and live load roof = LLroof). Where there are multiple load cases of one type, (LLred1, LLred2 etc) they represent all the different load cases in which loads of that particular type (live load reducible) was applied. |
| Beam Forces | Select this option to display beam forces on the screen for the currently selected story and load case. Forces are displayed along the length of the beam according to the Sign Convention (see Section 3.4.2). Beams will always be oriented from the lower to the higher numbered node (Node I is the lower node number on the beam span). All forces are displayed at the face of the beams (i.e. not at center-line) except for beams continuous over girders in which case a knife-edge support is assumed for the beams. Select the Show At Quarter Points option to display the forces at beam ends, and three points along the span. The distance to quarter and mid-span force is calculated based on the centerline span length. Select the type of force (Moment, Shear, or Torsion) to display. Click Apply to have the selection displayed on the screen. Note that forces will only be displayed on beams that have significant force (above some small limit) for the selected load case and story. Beam forces for live load cases display the unreduced live load forces. These forces are reduced according to the members Live Load Reduction Factor (see Section 3.3.9) when determining a beams design forces. The Beam Line Force Envelope Report (see Section 5.7) is based on the reduced live load forces. |
| A Note on Beam Deflections: | The computation of beam gravity deflections is performed during the analysis. Dead and Live Load deflections are calculated at 20 stations along beams with associated beam. No deflection data is computed or available for non-beam line beams. The selection of skip-loading and live load reduction in the Analysis - Criteria menu has a significant effect on the computed deflections as described in the technical section. No additional user input is necessary. The deflection values are not available from the screen only from the Reports Menu. |
| Column Forces | Select this option to display column forces on the screen for the currently selected story and load case. Forces are displayed at each end of the column in accordance with the Sign Convention (see Section 3.4.2). Columns are oriented from top to bottom (upper node to the lower node). All forces are displayed at the face of the columns where they are continuous. Select the type of force (Moment, Shear or Torsion) to display. Click Apply to have the selection displayed on the screen. Note that forces will only be displayed on columns that have significant (above some small limit) force for the selected load case and story. Column forces for live load cases display the unreduced live load forces. These forces are reduced according to the member's Live Load Reduction Factor (see Section 3.3.9) when determining a column's design forces. The Column Forces report (see Section 5.9) is based on the reduced live load forces. |
| Wall Forces | Select this option to display column forces on the screen for the currently selected story and load case. From this dialog, select the wall force (Shear, Moment or Axial) to display for the currently selected story and load case. Walls are meshed prior to analysis but the wall forces reported are the cumulative resultant of all the finite elements in the physical wall. This is true even for wall with openings that exist through the entire height or width of a physical wall, essentially breaking it into two or more physical walls. All live load forces are unreduced. Reported forces for wall members include axial force, major axis shear and major axis bending moment (overturning moment). The figure below shows the positive direction of wall member forces. |
| Show Force Diagram | Select this option to display force diagram on the screen for the currently selected story, load case and members. Forces are displayed only for beams and columns along their length according to the sign convention (see Section 3.4.2). |
| Scale Factor | Scale factor value is used to scale the member force diagram on the screen. The scale factor number is only used for representation. One may also specify a negative value of scale factor to show the diagram on the tension face of beams and columns. |
