{"id":33498,"date":"2026-04-27T12:53:59","date_gmt":"2026-04-27T12:53:59","guid":{"rendered":"https:\/\/protasoftware.com\/technical-manuals\/structural-modelling\/working-with-slabs\/"},"modified":"2026-06-19T12:37:46","modified_gmt":"2026-06-19T12:37:46","slug":"working-with-slabs","status":"publish","type":"wiki","link":"https:\/\/protasoftware.com\/wiki\/working-with-slabs\/","title":{"rendered":"Working With Slabs"},"content":{"rendered":"

Defining a New Slab<\/span><\/span><\/b><\/h1>\n
Before inserting a Slab member its reference axes should be defined.<\/span><\/span><\/span><\/div>\n
To define a new Slab member:<\/span><\/span><\/span><\/div>\n
    \n
  1. Display the storey level in the drawing area which will contain the slab.<\/span><\/span><\/li>\n
  2. Press the \u201c<\/span><\/span>Slab<\/span><\/span><\/i>\u201d button located in "<\/span><\/span>Modelling<\/span><\/span><\/i>" ribbon.<\/span><\/span><\/li>\n
  3. Slab "<\/span><\/span>Properties\u201d <\/span><\/span><\/i>dialog will appear <\/span>
    <\/span><\/span><\/li>\n
      \n
    1. If load cases and combinations has not been defined, there will be a prompt to generate them.<\/span><\/span><\/li>\n<\/ol>\n
    2. Edit the fields in the "<\/span><\/span>Slab Properties<\/span><\/span><\/i>" form. For example, enter the Slab Label in the "<\/span><\/span>Label<\/span><\/span><\/i>" field (max. 11 characters) and modify the slab thickness "<\/span><\/span>h<\/span><\/span><\/i>".<\/span><\/span><\/li>\n
    3. Press the \u201c<\/span><\/span>Loads<\/span><\/span><\/i>\u201d tab in the \u201c<\/span><\/span>Slab Properties<\/span><\/span><\/i>\u201d form to access the next page and define the dead and imposed loads of the slab. <\/span><\/span><\/li>\n
    4. In either the plan or 3D view, pick the position of the slab. <\/span>
      <\/span><\/span><\/li>\n
        \n
      1. By default, "<\/span><\/span>Beam Region<\/span><\/span><\/i>" is set as the insertion method. So, picking a closed region surrounded by beams and\/or walls will be sufficient to define the slab boundaries. For the other insertion methods see related topics further in this section.<\/span><\/span><\/li>\n<\/ol>\n
      2. Edges of the slab will be numbered in counter-clockwise direction and displayed in Graphic Editor, as first edge being the lower edge on plan.<\/span><\/span><\/li>\n<\/ol>\n

        Editing an Existing Slab<\/span><\/span><\/b>
        <\/span><\/h1>\n
        In order to edit an existing slab:<\/span><\/span><\/span><\/div>\n
          \n
        1. Select the slab.<\/span><\/span><\/li>\n
        2. Right-click and select \u201c<\/span><\/span>Properties<\/span><\/span><\/i>\u201d. (\u201c<\/span><\/span>Properties<\/span><\/span><\/i>\u201d can be accessed alternatively by pressing the \u201c<\/span><\/span>Slab<\/span><\/span><\/i>\u201d button).<\/span><\/span><\/li>\n
        3. Modify the fields such as "<\/span><\/span>Label<\/span><\/span><\/i>", "<\/span><\/span>h<\/span><\/span><\/i>" and\/or loadings in the "<\/span><\/span>Slab Properties<\/span><\/span><\/i>" form.<\/span><\/span><\/li>\n
        4. Press the "<\/span><\/span>Update<\/span><\/span><\/i>" button in the form.<\/span><\/span><\/li>\n<\/ol>\n
          You can repeat this process with as many members as you wish. One member at a time can be edited by this method. In order to update several slabs at once, you can use the "<\/span><\/span>Slab Table<\/span><\/span><\/i>" via right-click menu.<\/span><\/span><\/div>\n
          <\/span><\/div>\n

          Insert Slabs Automatically<\/span><\/span>
          <\/span><\/span><\/h1>\n
          Multiple slabs can be automatically inserted adjacent to selected beams.<\/span><\/span><\/div>\n
          To insert slabs automatically:<\/span><\/span><\/div>\n
          <\/span><\/div>\n
            \n
          1. Multiple select<\/span><\/span><\/i> <\/span><\/span><\/span>any beams at the boundary of intended slabs.<\/span><\/span><\/li>\n
          2. Click on<\/span> <\/span><\/span>Slab Properties<\/span><\/span><\/i> icon & input the required data. <\/span><\/span><\/li>\n
          3. Click on<\/span>  <\/span>Insert Slabs Automatically   <\/span><\/i>in <\/span>"Modelling"<\/span><\/i> ribbon<\/span> <\/span><\/i>. <\/span><\/span><\/span><\/li>\n<\/ol>\n

            Setting Slab Types Automatically<\/span><\/span>
            <\/h1>\n

            Slab types are used by the analytical or moment coefficient analysis and design of slab procedures. <\/span><\/span><\/span><\/p>\n

            You can use \u201c<\/span><\/span>Set Slab Types Automatically<\/span><\/span><\/i>\u201d form to assign the slab types considering the adjacent panels in the plan. <\/span><\/span><\/span>
            <\/span><\/span><\/div>\n
            In order to initiate this function : <\/span><\/span><\/span><\/div>\n
              \n
            1. Right click to the \u201c<\/span><\/span>Slabs<\/span><\/span><\/i>\u201d node in the \u201c<\/span><\/span>Structure Tree<\/span><\/span><\/i>\u201d and select "<\/span><\/span>Set Slab Types Automatically<\/span><\/span><\/i> <\/span><\/span><\/span>" menu option. <\/span><\/span><\/span>
              <\/span><\/li>\n
                \n
              1. In this case, the function will be applied to all slab panels in the model.<\/span><\/span><\/span>
                <\/span><\/li>\n<\/ol>\n
              2. Select one or more slabs and load the short-cut menu using the right mouse button and select \u201c<\/span>Set Slab Types Automatically<\/span><\/span><\/i>\u201d option. <\/span><\/span>
                <\/span><\/li>\n
                  \n
                1. In this case, the function will be applied to selected slab panels (or all slab panels if \u201c<\/span><\/span>Determine the Types of All Slabs in the Storey<\/span><\/span><\/i>\u201d is checked).<\/span><\/span>
                  <\/span><\/li>\n<\/ol>\n<\/ol>\n
                  The slab types will be assigned when the \u201cOK\u201d button is pressed.<\/span><\/div>\n
                  \"Info\"<\/p>\n
                  This option cannot determine the types of cantilever slabs and slab panels with more than 4 edges.<\/span><\/div>\n
                  Kindly refer to related topic : Analytical Strip (Moment Coefficient Method)<\/a><\/span><\/div>\n

                  <\/span><\/div>\n

                  Slab Table<\/span><\/span>
                  <\/h1>\n

                  You can use the "<\/span><\/span>Slab Table<\/span><\/span><\/i>" in the right-click menu to modify one or more existing slabs. All cells in the table are editable. You can use the cursor keys or mouse cursor to select a cell and edit the contents.<\/span><\/span><\/span>
                  <\/span><\/p>\n

                  The "<\/span><\/span>Search<\/span><\/span><\/i>" button can be used to find a specific member after typing the label to the "<\/span><\/span>Member<\/span><\/span><\/i>" field.<\/span><\/span><\/span>
                  <\/span><\/p>\n

                  You can close this dialog window using \u201c<\/span><\/span>Close<\/span><\/span><\/i>\u201d button. All the changes made in this window will be applied immediately. <\/span><\/span><\/span><\/p>\n

                  Refer to this article for more details : Display and Edit Member Properties<\/a><\/span><\/span><\/div>\n

                  Slab Load Decomposition<\/span><\/span>
                  <\/h1>\n

                  ProtaStructure transfers the loads from slabs automatically using the yield line theory. Optionally, FE slab load decomposition can be applied. <\/span><\/span><\/span><\/p>\n

                  For details see articel :<\/span><\/span> <\/span><\/span><\/span>Yield Line and FE Load Decomposition with Example<\/a> <\/span><\/span><\/span>
                  <\/span><\/div>\n

                  Beam loads may be viewed, edited or printed at any time selecting a beam and using the "<\/span><\/span>Edit Member Loads<\/span><\/span><\/i>" option in the shortcut menu accessed by right clicking the mouse<\/span><\/span><\/span><\/p>\n

                  Slab Properties<\/span>
                  <\/h1>\n

                  "<\/span><\/span><\/span> Slab Properties<\/span><\/span><\/i> " will be loaded when the "<\/span><\/span><\/span> Slab<\/span><\/span><\/i> " option in the "<\/span>Modelling<\/span><\/i>" ribbon is selected. A new slab can be defined by arranging the fields in the form and then by clicking on one or more regions surrounded by axis elements in the plan window.<\/span><\/span><\/span> <\/div>\n

                  The \u201c<\/span><\/span><\/span>Slab Properties<\/span><\/span><\/i>\u201d form can also be accessed after selecting an existing slab and then by right-clicking and choosing the \u201c<\/span><\/span><\/span>Properties<\/span><\/span><\/i>\u201d option in the shortcut menu. You can select a slab member by using one of the \u201c<\/span><\/span><\/span>Member Selection<\/span><\/span><\/i>\u201d methods described previously.<\/span><\/span><\/span><\/p>\n

                  When the \u201c<\/span><\/span>Slab Properties<\/span><\/span><\/i>\u201d form is open, right clicking a new slab member and selecting the \u201c<\/span><\/span>Select and Load Properties<\/span><\/span><\/i>\u201d option in the shortcut menu will load the properties of the new member in the same window.<\/span><\/span><\/span>
                  <\/span><\/p>\n

                  The "<\/span><\/span>Slab Properties<\/span><\/span><\/i> <\/span><\/span><\/span>" form has two tab pages named \u201c<\/span><\/span>General<\/span><\/span><\/i>\u201d and \u201c<\/span><\/span>Loads<\/span><\/span><\/i>\u201d. You can shift between the pages by pressing the related tab heading.<\/span><\/span><\/span>
                  <\/span><\/p>\n

                  The General <\/b>tab comprises the following fields:<\/span><\/span><\/span><\/p>\n

                  Slab Label<\/span><\/span><\/b>
                  <\/h2>\n
                  The label that will identify the slab can be entered in this field. This field (after formatting to be a proper label) is limited to 11 characters. A text control spin button exists to the right of the label field to facilitate the creation of successive label text.<\/span><\/span><\/span><\/span><\/div>\n
                  <\/div>\n
                  As in all member types, the slab member labels will be listed in the \u201cStructure Tree\u201d under the related storey heading. This list can be used to select a member by clicking a member label.<\/span><\/span><\/div>\n
                  <\/div>\n
                  Repeating member labels is not permitted in a building. During the insertion of members, new label will be given by the program if a repeating member label is detected.<\/span><\/span><\/div>\n

                  Slab Type<\/span><\/span><\/b>
                  <\/h2>\n

                  The boundary conditions of the slab are determined from its entry. "<\/span><\/span>Slab Type<\/span><\/span><\/i>" codes are used for the design of uniform slabs using the moment coefficients method.<\/span><\/span><\/span>
                  <\/span><\/p>\n

                  <\/span>
                  <\/span><\/p>\n

                  Available Slab Panel Types<\/b><\/u><\/i><\/span><\/span><\/span>
                  <\/span><\/p>\n

                  A button menu that contains all the possible types will appear when this field is clicked. You should make a selection from the menu according to the boundary conditions of the slab.<\/span><\/span><\/span><\/p>\n

                  Slab Type 1-9<\/b> :  This is used to set continuity edge of slab, i.e. whether there is an adjacent slab. This information is required to for design of slab using Analytical \/ Moment Coefficient Method. It does not affect the calculation of slab load onto beams. <\/span><\/span><\/span>
                  <\/span><\/div>\n

                  Slab Types 12 <\/b>is reserved for the rectangular "<\/span><\/span>Cantilever Slabs<\/span><\/span><\/i>\u201d. This is used by the Finite Element Slab Strips as well. <\/span><\/span><\/span>
                  <\/span><\/p>\n

                   This slab type is specifically used for modelling the one-way slabs, i.e. load transfer is only to 2 parallel beams.  Example, prefabricated slabs whose two parallel edges do not transfer load to the system, can be classified in this category.  The span direction can be input in "Design Angle" field below. <\/span><\/span><\/span><\/p>\n

                  \n
                  \"Notes\"<\/p>\n
                  For Finite Element Floor Analysis for one way slab, refer to this article <\/span>: One-Way Slabs with Orthotropic Shell Elements<\/a><\/div>\n

                  <\/span><\/div>\n<\/div>\n

                  \n
                  \n
                  Slab Thickness (h)<\/span><\/span><\/b><\/div>\n<\/div>\n<\/div>\n

                  You can enter the thickness of the slab ("<\/span><\/span>h<\/span><\/span><\/i>") in this field. The slab thickness value will appear in the plan window. If the thickness of the slab is smaller than the minimum slab thickness required, the program will sound an alarm and a warning note will appear in the status bar.<\/span><\/span><\/span><\/p>\n

                  Relative Level<\/span><\/span><\/b>
                  <\/h2>\n

                  In <\/span><\/span><\/span>order to define the relative top level of the slab you can use this field. According to the negative or positive values you entered, the slab will be lowered or raised from default top storey level.  <\/span><\/span>By this way, you can define slab systems with different elevations.  <\/span><\/p>\n

                  Analytically, slab diaphragm will always be formed at the top of storey level, regardless of the Relative Level input. <\/span><\/div>\n

                  Apply Z to Analytical Model<\/span><\/span><\/h3>\n
                  Checking this option will force the slab diaphragm to follow the "Relative Level" input in the analysis.  This may be preferable if : 
                  <\/span><\/span><\/div>\n
                    \n
                  1. The level difference is significant compared to the adjacent slabs. 
                    <\/span><\/span><\/li>\n
                  2. You <\/span>wish to mesh the slab in building analysis & accurately capture the level of slab analytically. Refer to this : <\/span>Include Slabs in Building Model – Finite Elements Mesh<\/a>
                    <\/span><\/li>\n<\/ol>\n

                    Concrete Cover<\/span><\/span><\/b>
                    <\/h2>\n

                    This field can be used to specify the nominal concrete cover measured from the bar face to the edge of the slab. The<\/span><\/span> <\/span><\/span><\/span>effective depth<\/span><\/span><\/u> <\/span><\/span><\/span>of the slab is calculated using this concrete cover, the size of the bars used and the layer number of the tension reinforcement.<\/span><\/span><\/span>
                    <\/span><\/p>\n

                    A global control of nominal concrete covers can be achieved by going to  tab "Building Setout<\/i>" > <\/span><\/span><\/span>"<\/span><\/span>Settings Center<\/span><\/span><\/i>" > "Slab" > "Design" > "Parameters"<\/span>.<\/span><\/p>\n

                    Label Position<\/span><\/span><\/b><\/h2>\n
                    <\/span><\/b><\/span> <\/div>\n

                    Slab label will be placed at the center of slab by default. Slab label position will shows in differently location based on the button. Red circle in the button represents the label position.<\/span><\/span><\/span><\/p>\n

                    Design Angle<\/span><\/span><\/b>
                    <\/h2>\n

                    Angle is used to define direction if load load transfer if a one way slab type <\/span><\/span> is used.  <\/span><\/span><\/span><\/p>\n

                    In addition, Angle also defines the primary reinforcement direction angle in finite element analysis of slabs : <\/span><\/div>\n
                      \n
                    1. The \u201c<\/span><\/span>M1<\/span><\/span><\/i>\u201d moment contours and \u201c<\/span><\/span>M1d<\/span><\/span><\/i>\u201d design moment contours of the slab will be generated along this direction in Finite Elements Floor Model Post-processor Window. <\/span><\/span><\/li>\n
                    2. The \u201c<\/span><\/span>M2<\/span><\/span><\/i>\u201d and \u201c<\/span><\/span>M2d<\/span><\/span><\/i>\u201d contours will be generated along perpendicular to the direction defined by this global angle.<\/span><\/span><\/li>\n<\/ol>\n

                      The direction defined by the \u201c<\/span><\/span>Angle<\/span><\/span><\/i>\u201d field is measured in degrees counter-clockwise with positive x-axis to be 0.<\/span><\/span><\/p>\n

                      Slab Insertion Methods<\/span><\/span><\/span><\/h2>\n
                      \n

                      A standard slab can be inserted in a region bounded by beams or by axes. The selection of slab insertion methods can be accessed by clicking the dropdown button.<\/span>
                      <\/span><\/span><\/p>\n


                      <\/span><\/p>\n

                      \"Notes\"<\/p>\n
                      The above methods are not applicable for the insertion of cantilever slabs<\/span><\/span>.<\/div>\n

                      <\/span><\/div>\n<\/div>\n

                      Axis Region<\/span><\/span><\/b>
                      <\/h3>\n
                      W<\/span>hen "Axis Region " method for defining slab insertion is selected, insertion axes can be defined simply by picking a point surrounded by axes.<\/span><\/span><\/div>\n
                      If there is more than one region (surrounded by axes) within a slab panel, then successive points can be picked by pressing (and holding down) the "Ctrl" key while picking points : <\/span><\/div>\n
                        \n
                      1. The regions must be selected one by one using an adjacent region every time. <\/span><\/li>\n
                      2. The insertion of the slab will be completed when the "Ctrl" key is released.<\/span><\/li>\n<\/ol>\n
                        <\/div>\n
                        <\/div>\n
                        Slab Insertion Using "Axis Region"<\/span><\/i><\/span><\/div>\n
                          \n
                        1. Distribution of loads to the adjacent beams (yield lines) will also be displayed if the "Ctrl" is used during slab insertion, even if there is only one region within the slab area.
                          <\/span><\/li>\n
                        2. The insertion axes will appear in the "Insertion Axes" frame during picking sorted in counter-clockwise order starting from the lower-left edge of the slab<\/span>.<\/li>\n<\/ol>\n

                          Beam Region (Default)<\/span><\/span><\/b>
                          <\/h3>\n
                          \n
                          This is the simplest method for inserting a slab. If the slab is completely surrounded by beams and\/or walls then this method can be used. Just pick a closed area (surrounded by beams and\/or walls) to insert the slab.<\/span><\/span><\/div>\n

                          <\/span>
                          <\/span><\/span><\/p>\n

                          Slab Insertion Using "Beam Region"<\/i><\/span><\/span><\/span><\/span><\/p>\n<\/div>\n

                          Pick Axis<\/span><\/span><\/b>
                          <\/h3>\n
                          \n

                          "Pick Axis" method can be used as a third slab definition method. In this method, you can define the slab by picking the axes surrounding the slab.<\/span>
                          <\/span><\/span><\/span><\/p>\n

                          To insert a new slab using this method : <\/span><\/span>
                          <\/span><\/div>\n
                            \n
                          1. First select \u201c<\/span><\/span>Pick Axis<\/span><\/span><\/i>\u201d and then pick the axes in any order (counter-clockwise or clock-wise) starting from any axis and finally re-select the first axis you have shown to end the insertion action. <\/span><\/span>
                            <\/span><\/li>\n
                          2. The new slab will be inserted to the region surrounded by the selected axes. <\/span><\/span>
                            <\/span><\/li>\n
                          3. Then, the insertion axes in the "<\/span><\/span>Slab Insertion<\/span><\/span><\/i>" frame should be cleared by click "Delete All Axes" in order to define a new slab.<\/span><\/span><\/li>\n<\/ol>\n
                            This method can be used when the other methods (especially \u201c<\/span><\/span>Beam Region<\/span><\/span><\/i>\u201d or \u201c<\/span><\/span>Axis Region<\/span><\/span><\/i>\u201d) are difficult to apply.<\/span><\/span><\/div>\n<\/div>\n

                            Pick Points<\/span><\/span><\/b>
                            <\/h3>\n
                            "Pick Points" method can be used as a fourth slab definition method. In this method, you can define the slab by picking the axis intersection points around the perimeter of the slab. For simple boundaries this option requires one less click per slab than the \u201cPick Axis\u201d option.<\/span><\/div>\n
                            To insert a new slab using this method :
                            <\/span><\/div>\n
                              \n
                            1. After pressing the \u201cInsertion\u201d button in the "Slab Properties" window, select \u201cPick Points\u201d method. 
                              <\/span><\/li>\n
                            2. Then, select an axis intersection point and continue selecting axis intersection points around the perimeter of the slab as required.
                              <\/span><\/li>\n
                            3. As soon as you click an intersection where an axis is found that goes back to the start point the slab is inserted.
                              <\/span><\/li>\n<\/ol>\n
                              This efficient method can be used when the other methods (especially \u201cBeam Region\u201d or \u201cAxis Region\u201d) are difficult to apply.<\/span><\/span><\/div>\n
                              \n
                              \"Notes\"In the case of an error while using this method, all previously defined axes can be deleted by pressing the \u201c<\/span><\/span>Delete All Axes<\/span><\/span><\/i>\u201d button then you can restart the definition of the slab.<\/span><\/span><\/span><\/div>\n<\/div>\n

                              Pick Closed Slab Edge<\/span><\/span><\/b>
                              <\/span><\/h3>\n
                              "Pick Points " method can be used as a fifth slab definition method.  In this method, you can define the slab by picking the a closed polyline. For simple boundaries this option requires only one  click compare to other methods.
                              <\/span><\/div>\n
                              To insert a new slab using this method, a closed polyline must be created before slab insertion.
                              <\/span><\/div>\n
                              This method is similar to "Beam Region" insertion method. The differences between "Beam Region" and "Pick Closed Slab Edge" are:
                              <\/span><\/div>\n
                              \n
                                \n
                              1. "Pick Closed Slab Edge" required a full closed polyline while "Beam Region" can depends on polyline only, beam only or combination of both to create slab.
                                <\/span><\/li>\n
                              2. "Pick Closed Slab Edge" will create slab based on one [1] single selected closed polyline while "Beam Region" creates slab based on multiple polyline (by subtracting overlapped region). 
                                Example below shows the triangular polyline was selected to insert slab:<\/span>
                                <\/span>
                                <\/span><\/li>\n<\/ol>\n
                                "Pick Closed Slab Edge" can be useful to create slab based on single polyline when there are a lot of overlapping polyline drawn on plan view. <\/span><\/div>\n<\/div>\n

                                Loads tab<\/span><\/h1>\n
                                <\/div>\n

                                <\/span><\/div>\n
                                The Loads tab consist of the following fields : <\/span><\/div>\n

                                Self Weight<\/span><\/span><\/b>
                                <\/span><\/h2>\n
                                The Self-weight (per area) of the slab will be calculated automatically using the "<\/span><\/span>Unit Weight of concrete<\/span><\/span><\/i>" defined in "<\/span><\/span>Materials<\/span><\/span><\/i>" section and "<\/span><\/span>Slab Thickness<\/span><\/span><\/i>".<\/span><\/span><\/div>\n
                                The calculated value cannot be manually edited. <\/span><\/span><\/span>In order to neglect the self weights of the members you have to set "<\/span><\/span>Unit Weight of concrete<\/span><\/span><\/i>" defined in "<\/span><\/span>Project Parameters<\/span><\/span><\/i>" section to zero. Alternatively, a negligible (very small) "Self Weight" value may be entered in this field.<\/span><\/span><\/div>\n
                                Otherwise, you may want to compensate the slab load by manually adjusting at the "Dead Load" field.<\/span><\/span><\/span><\/div>\n

                                Dead Load (Additional)<\/span><\/span><\/b>
                                <\/h2>\n

                                The calculated weight (per area) in the above field does not include any additional covers. To add additional weights such as ceiling plaster, fake ceiling, floor finishes, the "<\/span><\/span>Dead Load<\/span><\/span><\/i>" field under "Loads"<\/i> tab can be used.<\/span><\/span><\/span><\/p>\n

                                Imposed \/ Live Load<\/span><\/span><\/b>
                                <\/h2>\n

                                The imposed live loads (per area) on the slab can be defined using this field. Right-clicking on this field will provide access to standard imposed loads defined in the codes.<\/span><\/span><\/span><\/p>\n

                                Slab Does Not Contribute To Floor Diaphragm<\/span><\/span><\/b><\/h2>\n

                                Usually in the analysis of the building systems, slabs are considered to behave infinitely rigid in their planes, thus, forming rigid diaphragm action.<\/span><\/span><\/span>
                                <\/span><\/p>\n

                                If \u201c<\/span><\/span>Slab Does Not Contribute to Floor Diaphragm<\/span><\/span><\/i>\u201d is checked, that slab will not participate in rigid diaphragm action. <\/span><\/span><\/span>By this way, all the nodes linked to the corners of this slab will displace independent of rigid diaphragm.<\/span><\/span><\/p>\n

                                For a complete control over diaphragm formation on a storey level use \u201cModel Options\u201d in \u201cBuilding analysis\u201d form in the \u201cAnalysis\u201d ribbon. Refer to<\/span> :  <\/span>Diaphragm Modelling Example<\/span><\/a><\/span><\/span><\/div>\n

                                Creating of Rectangular Cantilever Slab<\/span><\/span><\/b>
                                <\/h1>\n
                                R<\/span>ectangular cantilever slab can be created by choosing "Type" = 12 by following steps : <\/span><\/span><\/div>\n
                                  \n
                                1. Click on Slab icon & choose Type = 12<\/b>. 
                                  <\/span><\/li>\n
                                2. Go to cantilever tab, input values, example cantilever length accordingly. 
                                  <\/span><\/li>\n
                                3. Pick first intersection of axis to define start of cantilever slab (i.e. "I" node of supporting beam)
                                  <\/span><\/li>\n
                                4. Pick second point to defined end of cantilever slab (i.e. "J" node of supporting beam) 
                                  <\/span><\/li>\n
                                5. Move cursor to the side where it is to be inserted (a grey preview will be shown)
                                  <\/span><\/li>\n
                                6. Pick third point to confirm and insert the cantilever slab. 
                                  <\/span><\/li>\n<\/ol>\n

                                  Cantilever tab <\/span><\/span>
                                  <\/span><\/h2>\n
                                  The cantilever tab will appear when Type 12 is selected. <\/span><\/div>\n
                                  <\/div>\n
                                  \n
                                  <\/div>\n
                                  <\/div>\n<\/div>\n

                                  Cantilever Sab Dimension "d" , "b-Slab", "L-Cant" <\/span><\/span><\/b>
                                  <\/h3>\n
                                    \n
                                  1. "d" is the distance from the reference point to the beginning of the slab. The reference point of the slab is always the first point picked during the insertion of the cantilever slab.
                                    <\/span><\/li>\n
                                  2. b-Slab" is the width measured along the supported edge.  If "b-Slab" = 0 then the slab is defined as spanning completely between the insertion points.
                                    <\/span><\/li>\n
                                  3. "L-Cant" is the cantilever length. 
                                    <\/span><\/li>\n<\/ol>\n
                                    \n
                                    \n

                                    Parapet Load<\/span><\/span><\/b><\/h3>\n<\/div>\n
                                    Parapet Load can be applied to the edge of a cantilever slab in kN\/m.  Parapet load is classified as dead load.<\/span><\/div>\n<\/div>\n
                                    <\/div>\n

                                    Creating Irregular Slab
                                    <\/span><\/h1>\n
                                    To create a non-rectangular or irregular slab, you can use "Slab \/ Column Edge" function :  <\/span><\/div>\n
                                      \n
                                    1. Click "Polyline Slab \/ Column Edge" icon in "Modelling" ribbon
                                      <\/span><\/li>\n
                                    2. Pick a point to define start of cantilever slab. Click continuously to define the edge of the cantilever slab. The method to draw the slab edge lines are similar to multi-segment axis.
                                      <\/span><\/li>\n
                                    3. At the last point, right-click and select "Finish" to end the insertion and the slab edge lines will be drawn.
                                      <\/span><\/li>\n
                                    4. Click on the Slab icon. In the Insertion Option, ensure that Beam Region is selected.
                                      <\/span><\/li>\n
                                    5. Ensure the selection of slab type is "Type = 1".
                                      <\/span><\/li>\n
                                    6. Click anywhere within the slab edge line and a new slab will be created.
                                      <\/span><\/li>\n<\/ol>\n
                                      <\/span><\/p>\n
                                      \"Notes\"Refer to this article for more details : <\/span>Working with <\/span>Slab\/Column Edge<\/span><\/a><\/span><\/div>\n


                                      <\/span><\/a><\/div>\n

                                      <\/div>\n","protected":false},"excerpt":{"rendered":"

                                      Defining a New Slab Before inserting a Slab member its reference axes should be defined. To define a new Slab member: Display the storey level…<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"template":"","meta":{"_whitepaper_youtube_videos":"","_whitepaper_youtube_url":"","_whitepaper_youtube_thumbnail":"","footnotes":""},"categories":[185],"whitepaper_topic":[],"whitepaper_product":[],"whitepaper_type":[],"class_list":["post-33498","wiki","type-wiki","status-publish","hentry","category-structural-modelling"],"yoast_head":"\nWorking With Slabs - Prota Software<\/title>\n<meta name=\"description\" content=\"Defining a New SlabBefore inserting a Slab member its reference axes should be defined.To define a new Slab member:Display the storey level in the drawing\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/protasoftware.com\/wiki\/working-with-slabs\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Prota Software\" \/>\n<meta property=\"og:description\" content=\"Defining a New SlabBefore inserting a Slab member its reference axes should be defined.To define a new Slab member:Display the storey level in the drawing\" \/>\n<meta property=\"og:url\" content=\"https:\/\/protasoftware.com\/wiki\/working-with-slabs\/\" \/>\n<meta property=\"og:site_name\" content=\"Prota Software\" \/>\n<meta property=\"article:modified_time\" content=\"2026-06-19T12:37:46+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/protasoftware.com\/wp-content\/uploads\/2026\/04\/prota-doc-ac00c6ed9851ba8eb3f2ef1a139eb97d.png\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:title\" content=\"Prota Software\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"15 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/protasoftware.com\\\/wiki\\\/working-with-slabs\\\/\",\"url\":\"https:\\\/\\\/protasoftware.com\\\/wiki\\\/working-with-slabs\\\/\",\"name\":\"Working With Slabs - 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