Creating a Building Structural Grid

You can create a building structural grid to define column line locations, the main beams between the columns, and other structural members within a building.

See Also
About Structural Grids
Activating a Story

Context:

Note: Many Building Grid options are toggles. The system highlights toggles when they are activated.

  1. If you have a building, activate the desired bottom story for the building grid.

    Building grids that extend through all stories in a building begin at the lowest story in the building.

    Note: You can create a building grid without a building model in the 3D area. In such cases, skip this step.

  2. Create a sketch for the grid on the active story as follows:
    1. From the Building section of the action bar, click Positioned Sketch on Story .

      Note: You can create a sketch using Sketcher.

    2. In the 3D area, sketch the lines and curves that intersect at desired column locations.
    3. In the Sketcher app, in the Sketch section of the action bar, click Exit App .

    You can make an orthogonal or a radial grid.

  3. From the Building section of the action bar, click Building Grid .
  4. In the Building Grid dialog box, select the Profile box and from the 3D area, select a sketch.

    You can select a sketch that contains an output profile.

  5. To change the number of stories for which the building grid is created, in Number of Stories, enter a value.

    Note: To make the structural grid extend through all the stories in the building, make the number of stories equal to or greater than the number of stories in the building.

  6. From the Bottom Story list, select a story.
  7. Expand Options and perform the following steps:

    1. To include slabs added to the project, click the Slab box and select one or more slabs.
    2. To use a reference plane other than or in addition to the top story, click the Reference Plane box and select one or more reference planes.
      Note: You can select the Include foundation reference planes check box to automatically include reference planes contained in the foundation product.

    1. In the Roof Thickness box, specify the distance from the top of the uppermost story to the top of the virtual roof.

      The virtual roof elevation is the sum of the uppermost story height and the Roof Thickness. The system previews the virtual roof elevation in the 3D area in green.

      The Roof Thickness value is the added to the uppermost story height to account for the space required for the roof slab. If a building grid reaches the uppermost story, the scale and twist values are measured from the primary slab of the grid's starting story to the virtual roof.

  8. To transform the grid, perform the following steps:
    1. Expand Scale and scale the grid.

      Option Description
      Using a Law
      1. Select the Use Law for Scale check box.
      2. From the tree, select a law.

      The system uses the law as a reference to scale the grid.

      Tip: Use a law to scale the grid nonlinearly.
      Manually
      1. In Start Scale, enter the scale of the grid at the bottom of the starting story.
      2. In End Scale, enter the scale of the top of the uppermost story of the grid.
        Note: If you have entered a Roof Thickness value, the End Scale value determines the scale at the virtual roof.

    2. Expand Twist and twist the grid.

      Option Description
      Using a law
      1. Select the Use Law for Twist check box.
      2. From the tree, select a law.

      The system uses the law to obtain twist angle values at each output grid plane.

      Tip: Use a law to twist the grid nonlinearly.
      Manually
      1. In Start Angle, enter the angle of the grid at the starting story.
      2. In End Angle, enter the angle of the uppermost story of the grid.

        Note: If you have entered a Roof Thickness value, the End angle determines the angle at the virtual roof.

    3. Click the Spine box.
    4. From the 3D area, select a spine.

      By default, the system uses the global z axis as the spine. While transforming the grid, the system scales and twists about the points where the spine intersects with the output grid planes.

      Important: The spine must intersect all output grid planes.

  9. Click .
    If you started the building grid without a building model in the 3D area, the Building Grid feature creates the building. It uses your entry for the number of stories in the structural grid as the number of stories in the building.

The system creates a building grid in the 3D area and in the tree, places Building Grid in Shell and Core in the Structure Grids node.