Wall Panels

The wall panel element allows you to easily model walls for in plane and out of plane loads. Wall panel data may be viewed and edited in two ways:

Graphically, in the Wall Panel Editor
Texturally, in the Wall Panels Spreadsheet.

Drawing Wall Panels

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There are several graphic-editing features that make the creation and modification of models quite easy. Use the Wall Panels button to use these features in the model view. To create new wall panels, you can draw them using a drawing grid or draw "dot to dot" existing nodes. Once you have created these items you can use other graphic features to apply loads and set boundary conditions.

You can set many of the wall panel properties up front or you can modify these properties after you draw them. Modifying properties is discussed in the next sections. See the Wall Panels topic for information on wall panels and their properties.

The Wall Panels button lets you graphically draw wall panels in your model. Enter the appropriate wall panel parameters, and draw wall panels between existing nodes or on the drawing grid. Notice that the coordinates of the node or grid point that is closest to your cursor, are displayed next to your cursor. The new wall panels will be shown on screen and will be recorded in the Wall Panels Spreadsheet.

To actually draw a wall panel, you have two options:

Modifying your Drawing Grid according to how you wish to lay out your wall panels.
1. Use the Create Wall Panels by Clicking on Grid Areas option.
2. Click in the grid areas formed by the intersecting grid lines.
  
  As you click on an area, a wall panel is automatically created in that area.
Creating wall panels by drawing a diagonal that defines it.
1. Click on the grid point or node that you want to be the start node for the diagonal.
2. Click on the end node for the diagonal.
  
  The wall panel "stretches" like a rubber band as you draw from node to node.

Note:

You must draw wall panels rectangular.
Wall panels must be oriented vertically in your model.

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The parameters shown are the same parameters that you would enter on the Wall Panels Spreadsheet.

To draw Wall Panels:

Open a model view, if you haven’t done so already.
1. Open the View ribbon.
2. Click the Open 3D View icon, to open a new view.
If you are not drawing between existing nodes, create a drawing grid or define nodes on the Node Coordinates spreadsheet.
Click the Wall Panels icon.
Set the Wall Panel properties in the ‘Properties’ panel.
(Optional) In the Properties panel, set any other properties (Additional, Reinforcements and/or Advanced) by expanding each section and entering the properties you want to use.
Click Apply to start drawing wall panels by clicking on the nodes or grid points, using the left mouse button.
You must click on two points, or click in grid areas.
To stop drawing altogether, right click or press the Esc key.

Note:

To draw more wall panels with different properties, press CTRL-D to recall the Wall Panel action.
You can also specify or edit wall panels in the Wall Panels Spreadsheet.
You can also view and edit wall panel properties by clicking on a wall panel.
You can undo any mistakes by clicking the Undo icon.
Drawing top to bottom or bottom to top determines the panel's local axes directions. See Wall Panel Local Axis for more information.

Modifying Wall Panels

There are two ways to modify wall panels. You can view and edit the member data in the Wall Panel spreadsheet or you can click a wall panel to view and edit its properties. You can also double click a wall panel to open the Wall Panel Editor.

A group of selected wall panels can be modified all at once by selecting multiple plates, then changing their properties in the Properties panel. See the Graphic Selection topic for more on selecting.

The parameters shown are the same as those used to define new wall panels.

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To modify Wall Panels:

Open a model view, if you haven’t done so already.
1. Open View ribbon.
2. Click the Open 3D View icon, to open a new view.
You can choose to modify a single wall panel at a time or to an entire selection of wall panels.
- To modify a single wall panel: Click on the wall panel and change the properties in the Properties panel.
- To modify a selection of wall panels: Select the walls collectively by clicking and dragging over them, then change the properties in the Properties panel.

Note:

To modify more wall panels with different parameters, press CTRL-D to recall the Wall Panels action.
You can also modify wall panels in the Wall Panels Spreadsheet.
You can undo any mistakes by clicking the Undo button.
The thickness option is only available if you are choosing a General or Concrete material. Wood and Masonry require you to change their thickness in the Design Rules spreadsheet.
For existing models of version 9.1.1 or earlier, all wall panels will be brought in using Custom regions/openings. Here we provide an option that will reset all wall panels to base their design on the Wall Design Rule.

Wall Panel Spreadsheets

Another way of editing wall panels is through the Wall Panel spreadsheet. This spreadsheet is accessible through the Explorer panel, Data Entry section and includes data on two tabs: Primary and Advanced.

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The following data columns hold the primary data for the wall panels:

Wall Panel Labels

You can assign a unique label to any or all of the wall panels. You can then refer to a wall panel by its label. Each label must be unique, so if you try to enter the same label more than once, you will get an error message. You can relabel wall panels at any time, with the Relabel Wall Panels option on the Tools menu.

Wall Panel Nodes

The A, B, C, and D node entries are used to define the 4 corner nodes of a wall panel. The nodes must all lie on the same plane, be oriented parallel to the vertical axis and be entered in either a clockwise or counter-clockwise sequence. They can not be adjusted from the spreadsheet.

Wall Panel Material Type and Material Set

The material set label links the wall panel with the desired material defined on the Material Spreadsheet.

Note: Currently wall panels can only be made up of concrete, masonry, wood or general materials.

Wall Panel Thickness

The thickness field on the Wall Panels Spreadsheet is the thickness of the element. This thickness is constant over the entire element. Note that the thickness for Masonry and Wood wall panels are set in the Design Rules spreadsheet. For concrete and general material walls the value is defined here.

Design Rule

This allows you to choose a specific design rule from the Design Rules spreadsheet. The design rule is where you can specify very detailed information for the wall.

Panel/Spacing

This shows the current panel for masonry and wood walls. Wood and masonry walls can require an iterative solution. This means that the panel properties used for a wall panel may change from solution to solution, so here is the place where that information is displayed. Note that the panel properties also show up in the output.

When you select a design rule for a wall panel, there may be a range of sheathing call-outs, stud spacings and bar/grout spacings. At the initial solution the program simply uses the first item in the list that meets the criteria of the design rule and then the optimization starts from there. This initial criteria is what will show up in the Panel/Spacing column. After you optimize your wall this panel criteria may update/change. If you want to reset all of these values to the original values, simply right click when in the Wall Panels spreadsheet and select Reset Wall Panels Design.

Note:

For masonry walls we show the current bar/grout spacing.
For wood walls we show the current sheathing call-out and the current stud spacing.
For concrete walls this column is not applicable, as the stiffness of the wall is not affected by the program optimization.

Reset Wall Panels Design

The Wall Panels spreadsheet lists the panel parameters designed by the program after solution. From the Primary tab, you can reset the wall panels design by selecting the Reset Wall Panels Design from the right-click menu. This resets the panel design to the parameters, based on the Wall Design Rule.

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Seismic Rule

This field defines a Seismic Design Rule and is applicable to concrete walls only. Please see the Concrete Wall - Seismic topic for more information.

Design Method

This is a column specific to wood wall panels and allows you to choose which design method you choose to work with: Segmented, Perforated or Force Transfer. See the Wood Wall Panels topic for more information. These design methods are not applicable for concrete, masonry, or general wall panels.

Note: Currently, wood wall panel design is only available for NDS design.

SSAF (Shear Stiffness Adjustment Factor)

This is a factor specific to wood wall panels that allows the user to manually adjust the shear stiffness of a particular wall panel. Because the program uses a finite element solution, the program does not automatically consider some contributions to the FEM deflections, such as nail slip. With this adjustment factor the user can match up the deflections from their hand calculations with the FEM node deflections at the top nodes in the wall.

Icr (In Plane and Out of Plane)

These values are considered for both masonry and concrete wall design and allow you to modify the stiffness of the wall for cracking considerations. This value will be multiplied by the Igross of the wall.

Masonry Walls

By default (if left blank) the program will use a value of 0.50 for both In-plane and Out-plane Icr Factor. This value comes from Section 3.1.5.2 of the ACI 530-11 code. If you have performed a cracked section analysis or want to override this default you can input it directly here.

Concrete Walls

By default (if left blank) the program will use a value of 0.70 for In-plane Icr Factor and 0.35 for Out-plane Icr Factor. These are the minimum factors for beams (Out-plane) and columns (In-plane) per ACI 318-14 Section 6.6.3.1.1 (ACI 318-11 Section 10.10.4.1). If you have performed a cracked section analysis or want to override this default you can input it directly here.

For service level analysis, the level of cracking will be significantly less. Therefore, the stiffness used in your analysis should be representative of the reduced loading and reduced cracking. Per the ACI 318-14 Section R6.6.3.2.2 (ACI 318-11 Section R10.10.4.1), the program will account for this increased stiffness by applying a factor of 1.43 to the cracked section properties for any load combination that has the “Service Load” flag checked on the Design tab of the Load Combinations Spreadsheet

Note:

This factor will only be used if the Use Cracked Sections checkbox is checked in the Concrete tab of Model Settings.
This factor (or 1.43*Icr) can not be greater than 1.0.

K Factor

This is the effective length factor and is available concrete, masonry and wood walls. If left blank this will be taken as 1.0.

Note:

For masonry this factor affects ACI 530-11 equations 2-16, 2-17, 2-19, 2-21, 2-22, 3-11, 3-12, 3-18, 3-19, and Section 3.3.5.3.
For wood this affects the C_p factor calculation (specifically F_cE) for wood compression capacity for both studs and chord design.

Cm In/Out

This input controls the Cm calculation for P-Little Delta calculations for concrete wall panels. If this is left blank the program will auto-calculate this value. See the P-LIttle Delta section of the Concrete Wall - Design topic for more information.

Activation

This column allows you define a wall panel as inactive or excluded. Please see the Inactive and Excluded Elements for more information.

Wall Panel Editor

The Wall Panel Editor lets you edit the detailed properties of a wall panel including openings, regions and boundary conditions. This window also provides design options and details for the specific panel, and is accessible by double-clicking on an existing wall panel.

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If the wall panel is drawn upper right to lower left it will be drawn with the panel's local x-axis going from left to right. If drawn lower right to upper left the panel's x-axis will go from right to left and is presented here as though you are looking at the back side of the panel.

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Note: There are many icons, dropdown lists and information shown depending on the type of wall panel you are working with. See the Masonry Wall - Modeling, Wood Wall - Design and Concrete Wall - Design topics for more information.

Create Openings

In the Wall Panel Editor, you can add rectangular openings to the wall panel.

To draw an opening:

Click the Openings icon on the Walls ribbon.

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Select two grid intersections which make up the two diagonal corners of your opening.

Notice that you can view your cursor coordinates next to your cursor. The opening dimension is also displayed based on the first click of the opening relative to the second click.

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(Optional) Right-click your mouse, to exit this tool.

Note:

Drawing an opening in a concrete wall will create a lintel above the opening. We will not design the lintel but we will give analysis results. See the Concrete Wall - Design topic on lintels.
Drawing an opening in a masonry wall will create a lintel above the opening. For more information on defining lintel geometry and design properties, see the Masonry Wall - Design topic on lintels.
Drawing an opening in wood wall will create a header above the opening. For more information on defining the header properties, see the Wood Wall - Design topic on headers.
Drawing an opening in a general wall panel, there is no header/lintel automatically created. The general wall panel is given as an option for analysis only.
Openings can not overlap a region. Regions must be deleted before you draw an opening in an area. After the opening is created you can go back and redraw the regions.
Openings must be drawn greater than 3 inches away from wall edges.

Creating Regions

Within the Wall Panel Editor, you can also create different rectangular regions within your wall panel. Regions are used to further define areas of your wall panel for use in analysis/design. If you do not specify a region in a wall panel without openings, then the entire wall panel is considered a region.

Automatically Draw a Region

To automatically draw regions:

Input your openings, if not already done.
Click the Auto icon in the ‘Regions’ section of the Walls ribbon

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The program defines regions as we would expect a user to want them.

Note: If the regions defined are not located correctly by the generator, you can delete the generated regions with the Delete button and redraw them manually. See below for more information on this.
(Optional) Right-click your mouse, to exit this tool.

Manually Draw a Region

To manually draw a region:

Click the Manual icon in the ‘Regions’ section of the Walls ribbon.

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Use your cursor to select two grid intersections which make up the diagonal corners of the region.

Similar to wall openings, local coordinates and region dimensions will be displayed next to the cursor in the Wall Panel Editor.
(Optional) Right-click your mouse, to exit this tool.

Note:

For masonry wall panels, there is a region editor that allows you to define design properties for the region. Double-click inside the boundary of the drawn region to open this editor. See the Masonry Wall - Design topic for region information. Note that design and analysis results are displayed by region.
For wood wall panels the design and analysis results are displayed by region.
For concrete wall design, the program will automatically create regions at solution around openings. If there are floors/diaphragms that cut through your wall, then separate regions/designs will be created above and below the floors/diaphragms.
For general wall panels we will not do any design for you. However, you can lay out your regions so that your analysis results will allow you to design your general wall panels much more easily.

Access Design Rule From Properties Panel

When using the Wall Panel Editor, you can view or edit an existing Design Rule or create a new design rule, by using the Properties panel.

To access the Wall Panel Design Rule options:

Go to the Properties panel.

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Click on the Design Rule ellipsis button.

Tip: You can also just double-click inside a wall panel in the Wall Panel Editor, to open the Review or Change Wall Design Rule.

The Review or Change Wall Design Rule window opens.

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The following table explains the available Design Rule options.

Wall Design Rule - Options

Option	Description
Create New	Create New lets you create a new Wall Design Rule to be applied to the wall.
View & Edit Existing	View & Edit Existing lets you view, as well as edit, the Wall Design Rule that is currently applied to the wall.

Boundary Conditions

Within the ‘Wall Panel Editor’, all boundary conditions are applied as continuous along a wall panel edge.

To set boundary conditions within the Wall Panel Editor:

Open the Walls ribbon, if not already open.

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Click the Boundary Conditions icon in the ‘Regions’ section.
Select your boundary condition criteria, and click the wall panel edge to apply the boundary condition too.

You can also apply boundary conditions to your wall panel outside of the Wall Panel Editor as well, but this is the only place where you can define a continuous boundary condition.

For wood wall panels, hold downs and straps are used in the program as well. For more information on adding hold-downs and straps, see the Wood Wall - Design topic.
(Optional) To exit out of this tool right-click your mouse.

Wall Grid

The drawing grid, which appears in the upper right corner of the Wall Panel Editor screen, gives the user options for drawing within the Wall Panel Editor window. The options include:

Snap Options allows you to provide snap points at the edges of the wall panel at quarter and third points.

Grid Increments allow you to set a drawing grid within the Wall Panel Editor separate from that in the main model view that you can snap to when drawing openings and regions. This field can work in two separate ways:

Single input increment: If you put a single value here (0.5 ft for example), this increment will be used across the entire wall until the end of the wall is reached.
Multiple input increments: If you have specific locations you wish to define, you can use this field to place exact grid points. Commas are used to delineate different grids and @ symbols can be used to apply the same increment multiple times (5, 10, 2@8, 3 for example). If you place multiple increments in and you are not yet to the end of the wall then the last increment defined will be used until the end of the wall is reached.

View Controls

In addition to the wall panel editing tools, the Wall Panel Editor window includes the view controls listed in the following table.

Wall View Controls

Icon	Description
	The Delete icon lets you delete openings, regions or boundary conditions from the wall panel.
	The Rendered icon turns rendering of the current model view on or off, depending on the current setting.
	The Nodes icon shows any nodes that fall in the plane of the wall panel, and allows you to snap to them when drawing regions or openings.
	The Wall Grid icon turns the display of the Drawing Grid on ro off, depending on the current setting.
	The Diaphragm icon turns the display of the Diaphragms on or off, depending on the current setting.
	The Detach Diaphragm icon lets you click on a diaphragm in the editor to detach it from the wall. The detached diaphragm then shows up in gray.
	The Zoom Extents icon redraws the wall panel to fit within the Wall Panel Editor window.
	The Loads button in the 3D View editing panel, turns the display of the wall panel loads on or off, depending on the current setting.
	The Print icon on the Quick Access toolbar, lets you print your current wall panel view.

Note:

There are also view controls specific to concrete and masonry. For more information see the Concrete Wall - Design and Masonry Wall - Design topic.

There are also view controls specific to wood. For more information see the Wood Wall - Design topic.

Wall Panel Local Axes

When a wall panel is drawn it comes along with a set of local axes. If the wall is drawn top left to bottom right versus bottom left to top right it will change the direction of the local axes.

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In most cases the local axes direction does not affect results. Here is a list where the local axis is important:

Applying Loads: Wall panel surface loads can be applied to the local axes directions. Thus, the local axes direction will affect the sign of the applied load.
Viewing Plate Contours: Wall plate contours can be viewed based on local axes, thus knowing the orientation is necessary to get meaningful information from these contours
Out-of-Plane Concrete Wall Design: Concrete cover can be different for each face of a concrete wall. Which face you are defining is based on the +z and -z local axes.

Note: Check out the Flip Axis command to allow you to change these local axes.

Loading

Wall panels can be loaded either directly or indirectly from supporting other elements (other walls, columns, beams, etc.). Line loads and distributed loads can be applied directly to wall panels, similar to how they are applied to members. These loads can be applied vertically or horizontally. Wall panel surface loads can also be applied directly to the wall.

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Load Attribution

In RISA-3D, the use of finite elements dictates how loads pass through wall panels. Load is attributed to the structure according to relative stiffnesses of elements. In concrete, wood and masonry design, many empirical equations are formed based on approximations or idealizations. Because of this, you may not get your loading in your wall panel elements (regions and lintels) to match hand calculations exactly. A prime example of this occurs with the 45 degree rule for lintels for masonry. According to theory, arching action occurs in lintels to the point that, if the top of your wall is a sufficient distance away, only the load in the triangular portion above your lintel would actually be taken into the lintel itself. Also, no load applied at the floor level would be felt by the lintel either. See the image below.

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Within RISA-3D, this idealization will not hold true. The wall panel is a finite element mesh that attributes load according to the plate mesh FEM behavior. The load that is getting into the lintel is a true representation of how the wall is actually working. There is still arch action taking place as you can tell if you look at the vertical force contours in the wall panel.

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In the image above, the red color is an area of very low axial force in the wall. Thus, you can see that, due to plate distribution of force, there is still arching action taking place. This arching action, however, will not be immune to additional loads added to the wall or the opening being located lower in the wall (as is assumed with the idealized arching action in many texts). Thus, though your loads for lintel design may not be identical to what idealized methods might consider, this is a rational loading for the geometry and loading input on the wall panel.

Meshing the Wall Panels

At solution time, the wall panels will be automatically meshed into quadrilateral plate elements. Unlike the plate elements created directly by the user, the automatically generated plate elements are transient in the program and will not be saved in the input file.

The wall panel meshing is treated similar to analysis results. When the results of an analysis are deleted, the wall panel mesh is cleared to be re-built during the next solution. When a solution results file is saved, the meshed elements will be included in that file.

Mesh Size

The global mesh size for the wall panels can be input on the Solution tab of the Model Settings window. The smaller the mesh size, the more accurate the analysis will be. However, smaller mesh size also leads to longer solution time and more memory usage. The default mesh size is 12 inches in RISA-3D.

Localized small mesh sizes are used in the lintel locations for masonry walls, in order to achieve more accuracy for the lintel forces.

Graphical Display of the Wall Panel Mesh

By default, the plate elements associated with the wall panels are not visible to the user. The mesh can be turned on using the setting on the Panels tab of the Model Display Options window. The Analysis Mesh check box turns the display of the wall panel mesh on or off.

Note: The display of the mesh is only available when there are active analysis results.

Point Constraints for the Panel Mesh

Point constraints are the locations within the wall panel that require connectivity to the meshed plate elements. The program automatically generates point constraints at the following locations:

Location of an existing node on the wall panel edges, region boundaries and opening boundaries

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Where beams intersects the wall panels (out-of-plane) on the wall panel edges, region boundaries and opening edges

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Location of an external boundary condition.

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Note: Unattached node that are located on the wall panels can be considered as point constraints and prolong the meshing time. It is highly recommended that the user delete any unattached nodes before solving.

Line Constraints for the Panel Mesh

Line constraints are the locations within the wall panel that require continuous connectivity to plate edges rather than a single point. The program will automatically generate line constraints at the following locations:

Opening edges.

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The edge and vertical centerline of a defined region.

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Where a diaphragm intersects the wall panel.

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Where a beam or column element intersects within the plane of the wall panel.

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Tips for Ensuring an Accurate Mesh

In order to generate an efficient mesh that gives accurate results, it is critical to place the line constraints and point constraints correctly. If line constraints or point constraints are very close to each other, the automesher will be forced to generate small sized elements in order to satisfy the constraints. Therefore, a large number of plate elements will be generated and the solution will be slowed down significantly.

The following guidelines should be followed to ensure a quality mesh:

Avoid generating very narrow regions and openings.
Avoid small offsets between the external boundary conditions with the location of the region boundaries and wall boundaries.
Avoid small offsets between opening edges with the region boundaries .
When a wall panel is intersected by another wall panel, diaphragms, beams or plate elements, keep in mind that the intersection is a line/point constraint. Avoid the small offsets between intersections with the region boundaries or opening edges inside the wall panel.

Merge Tolerance for Auto-Correction of Mesh

If the distance between the line constraints and point constraints are smaller than the merge tolerance specified on the Model Settings (which defaults to 0.12 inches) then the automesher will automatically snap the constraints together during the meshing. This can eliminate some of the meshing issues that occur in the examples above.