Create a concrete spiral beam

Tekla Structures
Tekla Structures

Create a concrete spiral beam

Use the Create concrete spiral beam command when you want to model spiral staircases, parking ramps, and complex architectural shapes, for example.

Basic concepts related to spiral beams

The images below illustrate some basic concepts related to the creation of spiral beams. Note that if you change the positioning, the entire geometry of the spiral beam changes.

(1) Start point (the first point picked)

(2) Center point (the second point picked)

(3) Direction of the rotation axis (the optional third point picked)

(4) Center axis

(5) Total rise: the distance from the start point to the end point, parallel to the center axis

(6) Rotation angle: the rotation angle of the spiral beam, given in degrees. Note: positive value = counter-clockwise rotation, negative value = clockwise rotation.

(7) Radius: the distance from the start point to the center point, perpendicular to the center axis

Create a spiral beam

  1. On the Concrete tab, click Beam > Spiral beam.
  2. Pick the start point.

  3. Pick the center point.

  4. To set the rotation axis in the work plane +Z direction, click the middle mouse button to finish.

    Alternatively, instead of clicking the middle mouse button, you can pick a second center axis point to define the direction of the rotation axis.

    Tekla Structures creates the spiral beam. For example:

  5. Click the spiral beam to select it.

    The contextual toolbar appears with the following options:

    (1) Rotation angle

    (2) Total rise

    (3) Twist angle at start

    (4) Twist angle at end

  6. To add more rotation, enter a bigger value in the Rotation angle box.
  7. To make the spiral more loose, enter a bigger value in the Total rise box.
  8. To change the radius, move the start point or center point.


  • Spiral beam has a single, constant radius.
  • Unfolding of spiral beams whose total rise is larger than 0.00 does not produce completely straight results in drawings. The amount of deviation in the part profile outlines and part length depends on several factors: the type, size, and length of the profile; the amount of total rise; and the amount of rotation angle and detailing used.
  • Spiral beams are not always untwisted in unfolding. If unequal twisting is applied to the start end and end end, the unfolded drawing shows an unfolded but twisted part as a result.
  • Connections and details may not work as expected with spiral beams.
  • DSTV export of spiral beams may not produce a correct result.
  • You cannot export spiral beams as parts in IFC export. If you are modeling cast-in-place structures with spiral beam, you can export the geometry to IFC as pour objects.

Concrete spiral beam properties

Use the Concrete spiral beam properties in the property pane to view and modify the properties of a concrete spiral beam. To open the properties, double-click the spiral beam. The file name extension of a concrete spiral beam property file is *.csb.

If you have customized the property pane layout, the list of properties may be different.





User-definable name of a beam.

The name can contain a maximum of 61 characters.

Tekla Structures uses part names in reports and in Document manager, and to identify parts of the same type.


Profile of the beam.


Material of the beam.


Type of finish.

Finish is user-definable. It describes how the part surface has been treated.


Use to group beams.

For example, you can display parts of different classes in different colors.


On plane

Beam's position on the work plane, relative to the beam's reference line.


Rotation of the beam around its axis on the work plane.

At depth

Position depth of the beam. The position is always perpendicular to the work plane.


Rotation angle

Rotation angle of the spiral beam, given in degrees.

Total rise

Distance from the start point to the end point, parallel to the center axis.

Twist angle at start

Twist angle at end

Twist +/- angle of the spiral beam at the start/end of the beam.

Cast unit

Cast unit numbering

Part prefix and start number for the part position number.

Cast unit

Indicate whether the column is precast or cast in place.

Pour phase

Pour phase of the cast-in-place parts. Use to separate pour objects from one another.

Concrete covers for rebar sets

Coordinate system

Select whether the concrete cover thickness of the rebar sets in the part is defined in the global coordinate system, or in the part's local coordinate system.

The default global and local cover thickness values are defined in the Options dialog box.

If you select the empty option, Tekla Structures uses the global values.

Top, Bottom, Sides, Front , Back, Start, End

To override global or local default values from the Options dialog box, define the cover thickness at each required part face.

IFC export

IFC entity

For IFC export, select the IFC entity type and subtype of the part. The available subtypes depend on the selected IFC entity.

You can select the IFC4 subtype among the predefined options, or you can select USERDEFINED and then enter any text in User-defined type (IFC4).

Subtype (IFC4)

User-defined type (IFC4)



Click the User-defined attributes button to open the user-defined attributes (UDAs) of the part. UDAs provide additional information about the part.

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