Create and modify patches

Tekla Structural Designer
2020
Tekla Structural Designer

Create and modify patches

You can apply rectangular patches of reinforcement to individual slab items to act in addition to the background reinforcement. After selecting the patch type, you can place patches in the model by clicking or boxing around elements in 2D or 3D views.

Overview of patches and patch types

Patches are used during the design of concrete slabs as a way of managing the physical and design data. Each patch defines a rectangular area of slab within which FE analysis results are collected, enabling Tekla Structural Designer to perform the design process. Design moments are calculated along result strips, embedded within each patch. Depending on the patch type, a patch can contain up to 6 result strips, catering for up to 3 strips of reinforcement in each of two perpendicular directions.

Tekla Structural Designer contains the following patch types:

  • Column patch: can be placed at column stack heads

  • Beam patch: can be placed along beams

  • Wall patch: can be placed along walls

  • Panel patch: can be placed at a specified position within the panel boundary

    • not restricted to a centralized position or to existing within one panel

    • can be positioned under loads

Patches can be either on the top or the bottom of the slab and may or may not have reinforcement defined in them. If you have not defined any reinforcement, Tekla Structural Designer uses the background reinforcement. If you have defined reinforcement, then for the top/bottom, x/y direction, you can optionally use the sum of the background + patch reinforcement option, if the patches are reasonably aligned.

Note:

Any patches may overlap on the plan view. However, during design, the eventual overlap is ignored.

Create column patches

  1. On the Design toolbar, click the arrow on the left side of the Patch list.
  2. In the list, select Patch Column.
  3. In the Properties window, adjust the patch properties according to your needs.
    1. To specify the patch size, type values in the Lx and Ly fields.
    2. To specify the layer of the patch, select the desired option in Surface.
    3. To have the reinforcement automatically designed, select the Autodesign option.
    Note:

    Only select the Consider patch surface moments only option if you do not want Tekla Structural Designer to consider the opposite surface.

    One example where you would need the option is when the check of slab reinforcement in the opposite surface fails, but another patch exists in the same location at that face. When the second patch is designed, additional reinforcement is provided at the surface, so the surface check is not required for the original patch.

  4. According to your needs, do one of the following:
    To Do this
    Place a patch over a specific column
    • Click a column node within the slab.

      Tekla Structural Designer creates a patch to the selected column.

    Place multiple patches
    1. Move the mouse pointer to one corner of an imaginary box that will encompass the columns to which you want to create patches.

    2. Hold down the left mouse button.

    3. Drag the mouse pointer to the opposite corner of the box.

    4. Release the mouse button.

      Tekla Structural Designer creates patches to all columns entirely within the box.

Create beam patches

  1. On the Design toolbar, click the arrow on the left side of the Patch list.
  2. In the list, select Patch Beam.
  3. In the Properties window, define the required patch width (perpendicular to the beam span) and the center slab width.

    Tekla Structural Designer recalculates the two end strips accordingly. The strips cannot be modified.

    Note:

    Only select the Consider patch surface moments only option if you do not want Tekla Structural Designer to consider the opposite surface.

    One example where you would need the option is when the check of slab reinforcement in the opposite surface fails, but another patch exists in the same location at that face. When the second patch is designed, additional reinforcement is provided at the surface, so the surface check is not required for the original patch.

  4. According to your needs, do one of the following:
    To Do this
    Place a patch over a specific beam span
    • Click the required beam span.

      Tekla Structural Designer creates a patch centered on and orientated to the beam center line.

    Place multiple patches
    1. Move the mouse pointer to one corner of an imaginary box that will encompass the beams to which you want to create patches.

    2. Hold down the left mouse button.

    3. Drag the mouse pointer to the opposite corner of the box.

    4. Release the mouse button.

      Tekla Structural Designer creates patches to all beams entirely within the box.

Create wall patches

  1. On the Design toolbar, click the arrow on the left side of the Patch list.
  2. In the list, select Patch Wall.
  3. In the Properties window, adjust the patch properties according to your needs.
    1. To specify the layer of the patch, select the desired option in Surface.
    2. To have the reinforcement automatically designed, select the Autodesign option.
    3. Define the required patch width perpendicular to the wall.
    Note:

    Only select the Consider patch surface moments only option if you do not want Tekla Structural Designer to consider the opposite surface.

    One example where you would need the option is when the check of slab reinforcement in the opposite surface fails, but another patch exists in the same location at that face. When the second patch is designed, additional reinforcement is provided at the surface, so the surface check is not required for the original patch.

  4. According to your needs, do one of the following:
    To Do this
    Create a patch along a specific wall
    1. In the Properties window, set Create Mode to Single Patch Along Wall.

    2. Click the required wall.

      Tekla Structural Designer creates a patch, centered on and orientated to the wall center line.

    Place an internal patch and two end patches along a specific wall
    1. In the Properties window, set Create Mode to Internal With End Patches.

    2. Click the required wall.

      Tekla Structural Designer creates an internal patch and two end patches, centered and orientated to the wall center line.

    Place an end patch at one end of a specific wall:
    1. In the Properties window, set Create Mode to End Patch at Wall End.

    2. Click near the required end of the wall.

      Tekla Structural Designer creates a patch at the end of the wall that is closest to the point that you clicked.

    Place an internal patch part way along a specific wall
    1. In the Properties window, set Create Mode to Internal Patch.

    2. Click to define the start point of the patch along the required wall.

    3. Click to define the end point of the patch along the required wall.

      Tekla Structural Designer creates a patch between the selected points.

    Create patches along multiple walls
    1. In the Properties window, set Create Mode to Single Patch Along Wall or Internal With End Patches.

    2. Move the mouse pointer to one corner of an imaginary box that will encompass the walls to which you want to create patches.

    3. Hold down the left mouse button.

    4. Drag the mouse pointer to the opposite corner of the box.

    5. Release the mouse button.

      Tekla Structural Designer creates patches to all walls entirely within the box.

Create panel patches

  1. On the Design toolbar, click the arrow on the left side of the Patch list.
  2. In the list, select Patch Panel.
  3. In the Properties window, adjust the patch properties according to your needs.
    1. To specify the patch size, type values in the Lx and Ly fields.
    2. To specify the layer of the patch, select the desired option in Surface.
    3. To have the reinforcement automatically designed, select the Autodesign option.
    Note:

    Only select the Consider patch surface moments only option if you do not want Tekla Structural Designer to consider the opposite surface.

    One example where you would need the option is when the check of slab reinforcement in the opposite surface fails, but another patch exists in the same location at that face. When the second patch is designed, additional reinforcement is provided at the surface, so the surface check is not required for the original patch.

  4. According to your needs, do one of the following:
    To Do this
    Place the patch at the centroid of a specific panel
    1. In the Properties window, ensure that the Create Patch at Centroid option is selected.

    2. Click anywhere within the required panel.

      Tekla Structural Designer creates a patch at the panel centroid.

    Place the patch elsewhere within a specific panel
    1. In the Properties window, ensure that the Create Patch at Centroid option is cleared.

    2. Still in the Properties window, do one of the following:

      • To define the patch by its corners, select the Define corner points option.

      • To define the patch by its center, clear the Define corner points option.

    3. In the panel, click the points that define the patch.

      Tekla Structural Designer creates a patch at the selected position.

    Create multiple centroid patches
    1. In the Properties window, ensure that the Create Patch at Centroid option is selected.

    2. Move the mouse pointer to one corner of an imaginary box that will encompass the panels to which you want to create patches.

    3. Hold down the left mouse button.

    4. Drag the mouse pointer to the opposite corner of the box.

    5. Release the mouse button.

      Tekla Structural Designer creates patches to the centroids of all panels entirely within the box.

Modify patch properties

  1. Hover the mouse pointer over the patch that you want to modify.

    The Select Entity tooltip appears.

  2. In the Select Entity tooltip, use the arrow keys to navigate to the patch name and press Enter.
  3. In the Properties window, modify the patch properties according to your needs.
    1. To specify the patch size, type values in the Lx and Ly fields.
    2. To specify the layer of the patch, select the desired option in Surface.
    3. To have the reinforcement automatically designed, select the Autodesign option.
    4. To specify the directions of the reinforcement that you want to design, select the appropriate option in Consider Strips.
    5. To specify the type and direction of the reinforcement that you want to design, select the appropriate option in Reinforcement.
    6. To specify the required width for each strip, type a value in the Width field.
    7. To specify whether each strip should be designed for the average or maximum design force, select the appropriate option in Design Force.

Resize patches

  1. Hover the mouse pointer over the patch that you want to resize.

    The Select Entity tooltip appears.

  2. In the Select Entity tooltip, use the arrow keys to navigate to the patch name and press Enter.
  3. Hover the mouse pointer over the patch edge or corner that you want to adjust.

    The Select Entity tooltip appears.

  4. In the Select Entity tooltip, use the arrow keys to navigate to the edge or corner node and press Enter.
  5. Hold down the left mouse button and drag to move the edge or corner.
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