Basic Regions

The Basic Region reinforcement is intended to provide a general reinforcement in the T1, T2, B1 and B2 layers of an area of slab to cover the general reinforcement design within that region. Basic regions can be defined to apply to specific FE surfaces or, alternatively, applied within drawn zones or regions. Drawn regions can be part of an FE surface or may run across the boundary of adjacent FE surfaces. Basic regions must be flat (planar) regions.

On first entering the Slab Design Module, the default layout is as shown below.

The left hand pane displays the design calculations. The central pane displays the graphics view of the model. The graphics windows can be controlled by the menus as in Masterframe. The right hand pane contains the controls for adding basic regions, defining the design parameters for the regions, carrying out the autodesign and displaying a range of results to assist in investigating the design.

Basic Controls - Adding, Copying and Deleting Basic Regions

The basic controls for adding, copying, deleting and selecting basic regions are the icons in the Basic Reinforcement Sets area. These icons are:

 - Add a new Basic Region

 - Copy a region (automatically adds a new region with the same settings as the copied Basic Rebar)

 - Delete a region

 - Select all regions

 - Invert current selection

 - List visible items only (lists only those basic regions currently displayed in the graphics window

Adding Basic Regions

A new Basic Region of rebar is added by first clicking on the  icon. This will add a new item to the list of basic regions and add the default properties to the property panel. Basic calculation pane will also display the default information. The layout of the screen is shown below.

The properties for a basic region can be set before assigning it to an FE surface or drawn region, or, alternatively, the region can be defined first and the design parameters set afterwards. Changes in the design output are dynamic so the calculation output will automatically update to reflect any changes made in the design parameters.

Basic Region Properties

The design parameters of the Basic Region are defined in the design parameters input area. This is the area below the Rebar Set names area. The default layout is shown below.

To navigate through the inputs, hover the mouse over the area and use the mouse wheel to scroll up and down.

The Basic Region properties area contains input to control how the Basic Region is to be defined, whether the design is to be automatic or manual, definitions for the reinforcement placement relative to the FE surface local axes definitions of the reinforcement in the top and bottom layers and controls over peak smoothing.

Selecting the Basic Region

Once a basic region is created, the method of creating the region to which the Rebar set is to apply is done by using the Placement Method drop down. There are two options for creating a basic region. To apply the basic region to an FE surface, select the "Selected FE Surfaces" option. To create a drawn region in a plane, use the drop down to select the "Drawn Region" option.

To apply a basic region to an FE surface, click on the  icon. The icon will change colour. Next, using the mouse to place the cursor over the boundary of the required FE surface. When the cursor is sufficiently close to the FE surface boundary, the FE surface will highlight in yellow. Next, click the mouse left button to apply the Basic Region to the FE surface. The calculation pane will now display the design calculations for the selected FE surface. These initial calculations will be based on the default reinforcement. A typical FE surface is shown highlighted in the image below.

Drawn regions are not not limited to a single FE surface. Therefore, a drawn region can be a subregion within an FE surface or it can be a region which crosses the boundary of 2 or more FE surfaces. This can be useful for dealing with areas of higher loading where a basic region with more reinforcement is required without applying the same reinforcement over a full FE surface. When the Drawn Region option is selected, the Place Current Sub Zone Reinforcement area will display in the right hand pane.

The Place Mode allows the selection method to be selected. These are:

Draw Polygons - allows the region to be created by drawing the boundary graphically

Draw Rectangle - creates a rectangular region by selecting two points graphically. The two points selected will form opposite corners of the rectangle

Pick Panel - allows the selection of internal panels. The FE surface must contain internal members, which may be FE Dummy members, to be able to pick panels. Full FE surfaces cannot be selected

The draw a region, click on the  icon. Next, select any FE surface in the same plane as you wish to create a Drawn Region. This does not have to be the same FE surface on which the drawn region will be created. This step is required only to define the correct plane for the drawn region. Once the region is defined, click on the  icon again to exit the apply mode.

The Edit tools provide options to amend the drawn regions. When creating a drawn region, it may be convenient to draw polygons which overlap. The internal lines can then be deleted using the  icon leaving just the boundary members.

It is possible to overlap drawn regions and regions applied to FE surfaces. In this instance the Basic Rebar applied to the FE surface will apply to those areas of the FE surface not also defined in a drawn region.

Defining the Basic Rebar design parameters

The design parameters for each Basic Rebar region are set or modified by selecting the required region, either by clicking on the region title in the Rebar Set Name area, of by hovering the mouse over the region boundary in the graphics area until the region highlight and then selecting that region by with the left mouse button. The design parameters panel will then show the inputs applied to the currently selected rebar region.

The design parameters area is divided into several sub categories. Each area is outlined below.

General

The General input allows the basic rebar area to be named. Each created basic rebar area is given a default name. The General area also allows the placement method to be selected. Each basic rebar set can be set to apply to a whole FE surface or to a drawn region within a plane. The default option for the placement method is 'Selected FE surfaces'/ The default layout is shown below.

To select the Drawn Region option, click on the Placement Method row and use the drop down option to pick the Drawn Regions option. The General area will show two additional options for use in defining the Drawn Regions, as shown below.

The Parent FE option is used to define the plane for the drawn region. The drawn region is not required to be placed within or overlapping with the Parent FE surface.

The 'Overwrite all other Basic' allows the drawn region to either provide reinforcement in addition to any basic region the drawn region overlaps, or to replace the basic region rebar within the area defined by the drawn region. When set to False, the drawn region will provide reinforcement in addition to the basic region(s), while setting the option to 'True' will means the basic rebar will be defined only by the drawn region.

Auto Design

Auto design can be turned on or off for each basic region. This is selected by highlighting the Auto Design row and selecting the required option from the drop down.

With no auto design, the basic rebar is fully determined by the user in the Bottom and Top bar areas. With auto design turned on, then the software will carry out an auto design and determine the reinforcement required to satisfy the design requirements of the basic region.

Each basic region can have the auto design set independently, allowing auto design for some basic regions and not others.

When the auto design is activated for a Basic Rebar zone by setting the Auto Design row to Auto Design Bars, the input area expands as shown below.

The bar sizes and spacings are defined in the Defaults area. However, by adding bar and spacings dimensions in the Bars Sizes and Bar Spacings row, it is possible to control the allow bar arrangement and sizes for use with the auto design. Multiple bar sizes and.or spacings can be input by separating the required dimensions, separated by commas.

Angle

The angle inputs allow the orientation of the selected basic region reinforcement to be be defined relative to the FE surface local x-axis. The orientation of the Direction 2 reinforcement can also be specified where the reinforcement bars are skewed relative to the direction 1 bars. The direction 2 bars can be skewed up to an angle of +/- 45 degrees.

 The orientation of the reinforcement can be checked visually by using the Drawing Options and selecting the Rebar Areas option then using the drop down to select the reinforcement layers.

When skew reinforcement is used, the area of the skewed reinforcement in resolved into the local x- and y-axes. Hence skewed direction 2 bars will also contribute to the amount of reinforcement in direction 1. The calculations for the design capacity of the slab will reflect this. The calculations will update automatically to reflect the inputs.

Bottom Reinforcement

The bottom reinforcement for the selected Basic Region is set in the Bottom Bars input area. The default layout is shown below. The default values are defined in the Defaults input area, which is accessed by clicking on the  icon.

Bottom bars - define whether or not the basic region has bottom reinforcement

Bottom cover - define the cover to the bottom bars for the selected basic region. An input of zero uses the default cover

Bottom Bars Dir 1 - displays the defined bottom reinforcement in direction 1

Bottom Bars Dir 2 - displays the defined bottom reinforcement in direction 2

Set Bottom B1 layer - displays the current set direction for the bottom B1 layer of reinforcement

To change the bottom reinforcement, both the rows can be expanded. The expanded Dir 1 area is shown below.

Both the bar diameter and bar spacing are defined by inputting the required values in the input rows.

When using the auto design for a basic region, the auto design reinforcement will be displayed in the input rows. These can be modified by inputting values, over writing the auto design. However, if the auto design is carried out again, then the bars will be determined by the autodesign.

Top Reinforcement

The top reinforcement for the selected Basic Region is set in the Top Bars input area. The default layout is shown below. The default values are defined in the Defaults input area, which is accessed by clicking on the  icon.

The top reinforcement is defined in the same manner as setting the bottom bars.

Design Forces

The design forces area provides inputs to control the design forces used in the design of the selected basic rebar region. With peak smoothing on, the software will use the shape of the contours to identify peak regions and apply peak smoothing over the specified peak smoothing radius.

Use peak Smoothing - allows peak smoothing to be turned on or off for the selected Basic Region

Peak Smoothing Radius - defines the radius over which to apply peak smoothing

Reinforcement Auto Design

If the reinforcement in the basic regions is set to auto design and the parameters have been defined within the Auto Design area, the auto design is then carried out using the options provided within the Auto Design menu area. The layout of this area is shown below.

The Defaults area can be accessed by clicking on the  icon. This will open the Slab Design Basic Data and Defaults menu, which can also be accessed by selecting the  icon. This area allows the default parameters for design to be reviewed or defined.

The Auto Design can be carried out for individual selected basic regions. This is done by selecting the required basic region either graphically or from the list of Basic Regions, then selecting the  icon. To carry out an auto design for all Basic Regions, select the  icon. Finally, to carry out the auto-design for all reinforcement zones, select the  icon.

Further control over the areas the auto design is carried out for can be achieved by using the Visible Only check box. The basic functions of the autodesign modes remain the same, but they are limited to only those which are currently visible on in the graphics display. For large models, the auto design can take a significant amount of time to complete and it may be desirable to limit the amount of the model for which the auto design is carried out at any one time by using the Masterframe viewing tools to carry out the auto design for parts of the model.

The Scan for failures option will scan all reinforcement regions and zones and identify those for which the current specified reinforcement is not satisfactory. After a scan for failures is complete. each subsequent press of the Scan icon will jump to the next region or zone for which the design fails.