With FE Floor Analysis, you can analyze and design floors under vertical loads only independently from the global 3D building analysis.

In this approach, the floor is isolated from the building and only gravity and imposed loads are applied. This allows engineers to simulate design scenarios where vertical loads govern.

When conduct a “FE Chase-down” analysis, where it analyze the floors (under vertical loads only) from top to bottom, iteratively applying the calculated column reactions onto the floor below. This methodology is preferred by some engineers, who would like to eliminate the 3D side effects of a global 3D FE Analysis such as the 3D frame effects and differential settlements due to relative axial rigidities. This method simulates the good old 2D hand calculation methods in a 3D environment.

Perform Finite Elements Floor Analysis

1. Select one or more than one floor and click "Floor Mesh and Analysis" to run FE Floor Analysis. All selected floors will be meshed and analysed at once. Click “Select/Deselect All” to select all storeys or de-select all storeys.
   
2. Beam, Slab, Column and Wall stiffness factors can be set automatically to make an allowance for cracking and creep. An automated calculation is provided for this purpose: see Cracking & Creep. 
3. "Include Column Sections in FE Model" setting controls the inclusion of column and wall outlines in the finite element analytical model.
1. A single node will be used for modelling the columns if this option is not checked. This option is very useful for reducing the support moments at column and wall nodes by considering the section of the column.
2. If you check this option, rigid links are provided to create a rigid column outline to reduce stress concentrations and spikes occurring around columns and walls.
   

This modelling option is created specifically for flat slab structures. Models may not be created successfully for beam/slab systems
4. If option "Display Analytical Before Analysis" is checked, this will allow you to examine/check the meshing generated in your layout before analysis. 
5. When the sparse solver option is checked, it will reduce the time required for analysis. For certain model types a dramatic reduction in the analysis time can be achieved, for other models it may be less significant.
6. "Include Upper Storey Column Loads" option should be checked when chase-down analysis is required. A symbol “▼” will be displayed next to storeys when chase-down analysis is done successfully.
   

ALL storeys must be selected and this option must be checked in order to perform chase-down analysis. This will ensure the result can merged correctly in later stage. For more details about merging result of beam/column, please refer to What is Merge FE Column/Beam result with Example
7. The minimum & maximum mesh size can be adjusted. Click "Floor Mesh and Analysis" to mesh the floor and perform analysis.
   

The key objective is to choose an ideal balance of Plate Element Size to produce minimum number of plates but still sufficient to an accurately replicate the "true" behavior of the slab (so analysis time is minimized). Generally, try to achieve 6 to 8 plates between the column heads. 

Post Analysis Processes and Report

1. Storey will be highlighted as green colour when FE Floor Analysis is completed. If “FE Chase-down” is performed, “▼” will be displayed next to the storey. Otherwise, it will be greyed.
   
2. After FE Floor Analysis is done, clicking "Display Analytical Model" will open "FE Storey and Foundation Model"  to view the visualized result for selected storey. See: FE Storey and Foundation Model.
3. Other than the visualized result, FE Floor Analysis result can be viewed and generated in text form after completion of the analysis without any errors.  The analysis result reports can be prepared for selected nodes, slabs, and/or frame members. In all tab pages, you select items to be included using the visible lists and then press the “Create Report” button to generate the report.
4. To examine the minimum and maximum of displacement, click “List Maximum Storey Displacement”.
5. After FE Chase-down is done, you will be able to merge the result with Building Analysis result.
6. After merged the result and close & reopen the dialog, "Axial Load Comparison Report" will provides a means of verifying the total dead load and live load applied to the building. It also can be used to cross-check:
1. slab loads have been correctly decomposed onto the supporting members. 
2. gravity load applied matches the Building Analysis total vertical reaction. 
3. gravity load applied matches the FE Chase-down total vertical reaction.
7. For FE Floor Analysis models, it should be noted that they don't include for the effects of pattern loading. It is not feasible to automate pattern loading to generate every possible worst case scenario for every conceivable irregular arrangement. If it is a concern in your design, it is suggested that amplifying the "Positive Moment Factor" (10 to 20%, i.e. 1.1 to 1.2) to allow for these effects. Output results that viewed in FE Storey and Foundation Models is factored using the values entered in these fields. 

These factors should be defined before clicking "Display Analytical Model" in dialog. 

FE Storey and Foundation Model 

1. Storeys list acts as "Storey Selector" which allows you switch the result of floors by click the relevant storey on the list. A right arrows ">>>" symbol indicates the current selected floor. A check sign ""means a valid FE Analysis exists for that floor while a cross sign "X" means that an  FE Analysis has been performed but it is not valid anymore. If an FE Analysis has not been performed for a specific floor, it will still be listed however it won't accessible. 
2. FE Floor Analysis is performing sub-frame analysis under vertical load cases/combinations only, hence only vertical load cases/combinations will be listed in FE Floor Analysis Post-processing model. Results will be displayed for selected load case or combination.
3. "Effect" panel will appear when "Contour" is toggled on in Contour tab. 

Effects Panel

1. Displacement: Displacement of the nodes along direction. 
2. F11: Horizontal Axial Force per unit length
3. F22: Vertical Axial Force per unit length
4. F12: Shear Force per unit length
   
5. V13: Out of plane shear force at face 1 acting towards local axis 3
   
6. V23: Out of plane shear force at face 2 acting towards local axis 3
7. M1: Moment about Direction-1 per unit length** (Local)
8. M2: Moment about Direction-2 per unit length** (Local)
9. M12: Twisting Moment per unit length
10. M11-bot: Design Moment about Direction-2 at bottom (allows Wood-Armer Adjustment)
11. M22-bot: Design Moment about the Direction-1 at bottom (allows Wood-Armer Adjustment)
12. M11-top: Design Moment about Direction-2 at top (allows Wood-Armer Adjustment)
13. M22-top:  Design Moment about the Direction-1 at top (allows Wood-Armer Adjustment)
14. As(d)1-bot (local): Required steel area in the bottom face of the slab in Direction-1
15. As(d)2-bot (local): Required steel area in the bottom face of the slab in Direction-2
16. As(d)1-top (local): Required steel area in the top face of the slab in Direction-1
17. As(d)2-top (local): Required steel area in the top face of the slab in Direction-2
18. As(d)1-bot (Wood-Armer): Required steel area in the bottom face of the slab in Direction-1 (Wood-Armer Effects included) 
19. As(d)2-bot (Wood-Armer): Required steel area in the bottom face of the slab in Direction-2 (Wood-Armer Effects included) 
20. As(d)1-top (Wood-Armer): Required steel area in the top face of the slab in Direction-1 (Wood-Armer Effects included) 
21. As(d)2-top (Wood-Armer): Required steel area in the top face of the slab in Direction-2 (Wood-Armer Effects included) 
22. Soil Pressure: The soil pressure applied on the node
23. Soil Pr. Threshold: The threshold plot of the soil pressure against the allowable soil stress value. 
    

Wood-Armer Effects 

The conception of determining equivalent moment is authored by Wood and Armer which takes into account twisting or torsional moment, on top of the pure bending moment in the principal orthogonal direction. 

Details concerning the method can be found, for instance, in R.H.Wood, "The reinforcement of slabs in accordance with a pre-determined field of moments", Concrete, February 1968, August 1968].

We recommend users consider the Wood-Amer effects in the design of slabs as it is generally recommended by most design references. 

Contours

Contours

If "Line Contours"  is toggled on individually, the contour line color will be shown in Black color. If it is toggled on together with " Colored Lines" , the contour lines colors will follow the contour colors itself. 

User Defined Contour

1. The "Effect" and "Loading" that selected for user defined contour. 
2. Click the "Update" button to update the intervals value according to contour count. 
3. Contour interval values will automatic generated by program based on the result and contour count. 
4. Contour Legend format that going to use in user defined contour. 
5. Input or/and select the options and click "Update" to update the interval value & label of contours. 
6. Click "Redraw" to regenerate/update the user defined contour. 

Threshold Contours

Slab Strip Diagram

1. If Building Analysis is adopted in model, ensure that floors are meshed in Building Analysis. 
2. After analysis is done, select FE Slab strip on the model. 
3. Right-click and select "Strip Profile"
4. Alternatively, slab strip diagram also can be generated through the same menu button on the slab strip contextual ribbon tab tat appears when the slab strip is selected.  

      

1. Open Analytical Model for FE Floor Analysis or Building Analysis
2. Go to Result tab, select slab strip you want to review from the Slab Strip List. This will display the moment diagrams of selected strip on the analytical view
3. To view the detailed profile, select a slab strip on the analytical model, right-click > select "Slab Strip Diagram Profile"