Wall (Geometry)

Plane wall property	Description
Icon
Modules where available
Function	Line support in
	Shear or load-bearing wall region
	Unit section of long-extensional object (tunnels, dams, retaining walls et.)
	Structural wall in
Reference plane position	Vertical in
	Global X-Y plane
Geometry	Any shape
Thickness	Constant or variable
Hole	Available
Eccentricity	Only for display
Edge connection	Rigid, hinged, elastic (spring) linear or non-linear
Material	Steel, concrete, timber and general
Orthotropic feature	Available in
Load direction	Arbitrary in
	Planar, global X-Y plane
Load type	All point, line load and surface load in
Available analysis results	Reaction forces in
	Displacement, internal forces, stresses, stability and vibration shape in
Available design	RC design in
	Timber design in
Default Short Command	WL

Table: Wall properties

Figure: Wall function by FEM-Design modules

Definition steps

The wall definition depends on what module is used for modeling:
 

	Wall is a line support, so its base line has to be defined with a given height and constant/variable thickness as a straight or curved line.
	The only modeling object is the Wall, which is a region with constant or variable thickness, so its reference plane has to be defined as a rectangle, circular, polygonal or arbitrary shaped region. Holes can be added to it.
	The only modeling object is the Wall, which is a region with unit (=1) thickness, so its reference plane has to be defined as a rectangle, circular, polygonal or arbitrary shaped region. Holes can be added to it.
	Wall is a region in vertical position, so the base line has to be defined with given height and constant/variable thickness as a straight or curved line. Holes can be added to it.

1. If needed (and available in the current FEM-Design module), set a proper position for the working plane.
2. Start  Wall command from tabmenu and choose Define.
   

3. Set the properties of the new wall at  Default settings:
   

   • Identifier (General)
     The program automatically generates it, but you can define custom value. Identifier (ID and Position) number can be displayed in model view (Display settings).
   • Height (h) (General)
     In  the height can be set in the dialog, but in 3D modules only in the Wall command’s tool palette.

     	- In 3D modules, the sign (positive or negative) of the Height value defines the location of the Wall (Straight line).
     	- In , the position of the wall support can be set according to slab position: “Above slab” or “Under slab”. It also defines the location of the base line.

   • Alignment and Eccentricity (General)
     With alignment the position of the reference base line or the reference region can be set to left/front, center or right/back.
     Eccentricity (e) is handled the same was as in 3D Plate.
     Eccentricity value can be displayed in model view (Display settings).

     While modeling, think about the reference plane/reference line connections with each other. Connecting edged “perfectly” results correct and “nice” finite element mesh. If they intersect each other with small distances, the outcome of mesh generation may be very small finite elements or unexpected mesh regions. The next figure shows an example for possible (recommended or not) wall connection to slab edge.

     
     Figure: Recommended modeling of plate-wall edge connection (no calculation differences in case 1. and 2.)

   • Thickness (General)
     In , the thickness values (t1 in the start point and t2 in the end point) can be set directly in the settings dialog. The measurement of the thickness depends on the Alignment and Eccentricity settings.
     
     Figure: Variable thickness and eccentricity
     In , the thickness value is fixed. It is always 1m, so only region(s) with unit thickness (section) can be defined.
     In , the thickness value can be constant or variable like plate regions. Because walls are regions in the Wall module like plates in Plate module, the definition way of constant and variable thickness is the same. In the dialog, only constant thickness (t1=t2=t3) can be set, but with Variable thickness tool (same with Plate’s Variable thickness tool) t values can be modified separately to define wall regions with variable thickness.

   • Orthotropic features (General)
     This option is available in  modules. The ratio between the E1 and E2 elasticity modules in the main directions can be set here. So, if the value is 1, the new wall will be isotropic, otherwise it is orthotropic. The orthotropy direction can be set with the angle between E1 direction and the wall’s local x’ axis (Alpha).

     In    modules the local x’ axis is always parallel with the global X axis.

   • Statical System (Connections) (General)
     In , the support conditions (General) of the top and bottom wall ends can be set to fully rigid or fully hinged. Because, Walls are line supports further line/point support is not needed to define at Wall end.
   • Allow uplift (General)
     Available in  only. “Uplift” behavior can be modeled by activating this option. It works in case of tensional reaction force.

     In 3D modules, “uplift” can be modeled with non-linear Line support settings.

   • Material
     Any type of materials can be set for wall Analysis, but design can be run for concrete and timber walls only depending on the current FEM-Design module. The applied material name can be displayed in model view (Display settings).

4. In  module, predefined connections for wall edges can be set to rigid, hinged, “No shear” or so-called User defined with the tool palette’s Edges Setup option.
   
   Figure: Predefined edge connections

   Use the Edge connection tool to modify the default connections by the selected edges of a predefined wall. Hinged, rigid, semi-rigid (spring), free connections can be set with linear and non-linear behavior.

   “No shear” macro defines edge connection with predefined “No shear” rigidity type on the defined wall’s bottom edge.
   It is the recommended wall definition method to create a non-bracing system element.
   “No shear” rigidity type settings with free local x’ motion rigidity:
   
    

   If a wall connect to slab at a common edge and you would like to define hinged connection between them, only one edge connection (for plate or wall) has to be defined hinged and the other has to be kept as rigid. So, applying hinged edge connection for both plate and wall at their linked edge is not allowed to avoid instability in finite element modeling. The figure shows the possibilities to model the same hinged connection in two ways. Figure: Modeling the same hinged wall-plate edge connection in two ways The previous rule is also true for wall support in   module: if, you would like to model hinged wall support at a plate edge, define hinged statical connection for wall (top or bottom depending on the wall position) and set the plate edge connection to rigid, or, define rigid wall support and hinged edge for plate.

5. Choose a geometry definition method for the wall’s reference line/plane (set by Alignment and Eccentricity) and create the wall with co-ordinates or by picking points in the drawing area.
   In   modules, the walls are regions in the Global XY working plane.

   In these wall modules the dead-load is orientated in Global Y direction, although the dead-load is orientation in Global Z direction in all other modules.

   
   Figure: Wall region with holes, loads and supports in Wall and Plane Strain modules
   In   module, wall is a line support, so it has to be defined with its base/reference line. Although walls are planar objects in  modules, they can be defined with their reference lines, because of the fixed vertical position. The lines can be straight or “curved”. The “curved” means real arc and circle in  module, while it means the combination of straight lines (wall sections) in the 3D modules. In the second case the “curved walls” are built up by planar region members (curved finite elements are not available in FEM-Design), and the resolution of the curve approximation can be set by the peripheral angle of the sections (Alpha).
   
   
   Figure: “Curved” wall definition in 3D modules

   In the 3D modules, if you would like to connect a plate to “curved” walls at the edges, define polygonal slab instead of curved-edge slab. In case of curved plate, small regions are cut by the connected wall, and that results finite elements with very small angle.

   
   Figure: “Curved” wall definition in 3D modules

Optional steps:

6. Modify default thickness (Variable thickness)
   Constant wall thickness can be fast modified with the  Properties tool. Just select the wall(s) and set a new value under General Tab. In  modules, you can define variable thickness with t1 and t2 values too.
   In  modules, constant thickness can be changed to variable (linear distribution), or reverse, with the   Variable thickness tool.
   Defining wall with variable thickness is similar as done in case of a Plate.
7. Modify the default edge connections with  . Just select the wall and then its edge(s) to set connection conditions (rigid, hinged, free or semi-rigid (spring)), and finally set the requested motion and rotation settings. See the definition steps and possibilities at Plate.
8. Add hole with   tool (see hole definition in plates).
   Except of  module where wall is support, holes and cuttings can be defined in walls.
   In 3D modules, select a wall region and define hole in it or cut it by using a geometry mode. Selecting a wall displays the UCS in the reference plane of the wall.
   In   modules, just define hole or cutting by using a geometry mode in the required wall reference plane. Selection of the host wall is needed, if the hole region intersects more than one regions.
9. Modify the reference line/plane geometry with the Edit menu commands valid for lines/region elements.
10. Modify the wall properties with the  Properties tool of the Wall tool palette.
11. In Plate module, the  Info tool displays the support stiffness (motion and rotation) values of the wall ends (start and end point) valid in the wall local co-ordinate system.
    In the other design modules, information (the volume of the wall solid and the position of its centre of gravity) about a selected wall can be inquired with the  Info tool. A drawing point can be placed in the wall’s centre of gravity, if needed.
12. Set the display settings of walls at Settings > All > Display > Shell (see Plate display settings).
13. The walls are stored on “Walls” Object layers. At layer settings, the default color and pen width can be set for all plate regions. The color and pen width settings by selected plate elements can be modified by Edit > Properties > Change appearance.