Analysis part properties

Tekla Structures
2021
Tekla Structures

Analysis part properties

Use the options in a part’s analysis properties dialog box (for example, Beam Analysis Properties) to define how Tekla Structures handles the part in the analysis. The settings you have available in the dialog box vary depending on the part type and analysis class. The table below lists all settings regardless of the part type and the analysis class.

Analysis tab

Use the Analysis tab to define the analysis properties of a part.

Option

Description

Class

Defines how the part is handled in the analysis.

The selected Class defines which analysis properties are available. For example, plates have different properties from columns.

Filter

(Rigid diaphragm properties)

Only available when the Class is Contour plate - Rigid diaphragm or Slab - Rigid diaphragm.

Defines the filter used when filtering objects for a rigid diaphragm.

Nodes that belong to a part matching the filter will be connected to the rigid diaphragm. For example, you can use a column filter to connect only column nodes to rigid diaphragms.

Built-up section mode

Indicates the role of the part in a built-up section that consists of a main part and one or more sub-parts. In the analysis, sub-parts are merged to the main part.

The options are:

  • Automatic

  • Not part of built-up section

    Disconnects the part from a built-up section.

  • Main part of built-up section

    Always use to define the main part of a built-up section.

  • Sub-part of built-up section

  • Beam sub-part of built-up section

    Defines that the part is a part of the built-up section when the main part of the built-up section is a beam.

  • Column sub-part of built-up section

    Defines that the part is a part of the built-up section when the main part of the built-up section is a column.

Design group

Defines to which design group the part belongs. Used in optimization.

Automatic update

Defines if the analysis part is updated according to the changes in the physical model.

The options are:

  • Yes - Physical model changes are considered

  • No - Physical model changes are ignored

Start releases tab, End releases tab

Use the Start releases and End releases tabs to define the support conditions and the degrees of freedom for the part ends.

The Start releases tab relates to the first part end (yellow handle), the End releases tab to the second part end (magenta handle).

Option

Description

Start or End

Defines which of the predefined or user-defined combinations for end conditions is used for part start or end.

These are the predefined options:

(Not available with Tekla Structural Designer)

(Not available with Tekla Structural Designer)

They automatically set the support condition and degrees of freedom.

You can modify a predefined combination to suit your needs. If you do that, Tekla Structures indicates it with this option:

Support condition

Not available with Tekla Structural Designer.

Defines the support condition.

The options are:

  • Connected

    Part end is connected to an intermediate analysis node (another part).

    Indicate degrees of freedom for the node.

  • Supported

    Part end is the ultimate support for a superstructure (for example, the foot of a column in a frame).

    Indicate degrees of freedom for the support.

Rotation

Only available if Support condition is Supported.

Defines whether the support is rotated.

The options are:

  • Not rotated

  • Rotated

If you select Rotated, you can define the rotation around the local x or y axis, or you can set the rotation by the current work plane by clicking Set rotation by current work plane.

Ux

Uy

Uz

Define the translational degrees of freedom (displacements) in the global x, y, and z directions.

The options are:

  • Free

  • Fixed

  • Spring

If you select Spring, enter the translational spring constant. The units depend on the settings in File menu > Settings > Options > Units and decimals.

Rx

Ry

Rz

Define the rotational degrees of freedom (rotations) in the global x, y, and z directions.

The options are:

  • Pinned

  • Fixed

  • Spring

  • Partial release

If you select Spring, enter the rotational spring constant. The units depend on the settings in File menu > Settings > Options > Units and decimals.

Use Partial release to specify if the degree of connectivity is between fixed and pinned. Enter a value between 0 (fixed) and 1 (pinned).

Composite tab

Use the Composite tab with STAAD.Pro to define the analysis properties of the slab in a composite beam.

Option

Description

Composite beam

Defines whether the composition is a:

  • Non-composite beam

  • Composite beam

  • Automatic composite beam

Material

Defines the material of the slab.

Thickness

Defines the thickness of the slab.

Effective slab width

Defines if the effective slab width is calculated automatically or based on the values you enter.

You can define different values for the left and right side of the beam.

Automatic values are calculated in relation to the span length.

Spanning tab

Use the Spanning tab to define the analysis and load distribution properties of a one-way or two-way slab system.

Option

Description

Spanning

Defines in which directions the part carries loads.

The options are:

  • Single spanning plate carries loads in the direction of the primary axis. Beams or columns parallel to the spanning direction are not connected to the part, and will not carry loads from the part.

  • Double spanning part carries loads along the primary and secondary axes. Beams or columns in both directions will carry loads from the part.

Primary axis direction

Defines the direction of the primary axis in one of the following ways:

  • Enter 1 in the box (x, y, or z) which is parallel to the primary axis direction.

  • Enter values in multiple boxes to define the components of a direction vector.

  • Click Parallel to part, and then select a part in the model that is parallel to the direction.

  • Click Perpendicular to part, and then select a part in the model that is perpendicular to the direction.

To check the primary spanning direction of a selected part in a model view, click Show direction on selected members. Tekla Structures indicates the primary direction using a red line.

Loading tab

Use the Loading tab to include a part as loads in analysis models.

Option

Description

Generate self weight load

Analysis models include the part weight, for example a deck, as a load even if the part is not otherwise included in the analysis models.

If the part is included in an analysis model, so is its self-weight. The option No works only with the analysis classes Ignore and Rigid diaphragm.

List boxes for additional loads

Enter slab live load or additional self-weight (screed, services) using three additional loads with a load group name and magnitude. The directions of these loads follow the direction of the load group to which they belong.

Part names

Use this filter to ensure that the area load from the slab is transferred to the correct parts, for example, beams supporting the slab. Typically, you would enter the beam name as the filter value.

Use continuous structure load distribution

Use to assign most of the load to the middle supports on continuous structures.

Design tab

Use the Design tab in the analysis part properties dialog box to view and modify the design properties of an individual part in an analysis model. Design properties are properties which can vary, according to the design code and the material of the part (for example, design settings, factors, and limits).

Position tab

Use the Position tab to define the location and offsets of an analysis part.

Option

Description

Axis

Defines the location of the analysis part in relation to the corresponding physical part.

The location of the analysis axis of a part defines where the part meets with other parts and where Tekla Structures creates nodes in analysis models.

The options are:

If you select Neutral axis, Tekla Structures takes the part location and end offsets into account when it creates nodes. If you select either of the Reference axis options, Tekla Structures creates nodes at part reference points.

Keep axis position

Defines whether the axis position is kept or changed according to changes in the physical model.

The options are:

  • No

    The axis is free to move when snapping end positions to nearby objects. Use this option for secondary members.

  • Partial - keep in major direction

    The axis is free to move partially, but the member is not moved in the major (stronger) direction of the part profile.

  • Partial - keep in minor direction

    The axis is free to move partially, but the member is not moved in the minor (weaker) direction of the part profile.

  • Yes

    The axis is not moved, but the end positions can move along the axis (thus extending or shortening the member).

  • Yes - Keep end positions also

    The axis and the end positions of the member are not changed.

Connectivity

Defines whether the member snaps or connects with rigid links to other members.

The options are:

  • Automatic

    The member snaps or connects with rigid links to other members.

  • Manual

    The member does not snap or connect with rigid links to other members. Automatic connectivity to other members is created only if the member position matches the other member exactly.

Axis modifier X

Axis modifier Y

Axis modifier Z

Define whether the member location is bound to global coordinates, grid line, or neither.

The options are:

  • None

    The member location is not bound.

  • Fixed coordinate

    The member location is bound to the coordinate you enter in the X, Y, or Z box.

  • Nearest grid

    The member is bound to the nearest grid line (the snap zone is 1000 mm).

Offset

Use to move the analysis part in the global x, y, and z directions.

Longitudinal offset mode

Defines whether the longitudinal end offsets Dx of the physical part are used from the physical part properties.

The options are:

  • Offsets are not considered

  • Only extensions are considered

  • Offsets are always considered

Bar attributes tab

Use the Bar attributes tab in a frame object’s (beam, column, or brace) analysis properties dialog box to define the properties of its analysis bars.

You can use the options on this tab when the analysis class of the analysis part is Beam, Column, or Secondary.

Option

Description

Start offset

End offset

Calculate offsets to account for longitudinal eccentricity at the member end (resulting in a bending moment).

These offsets have no effect on the topology on the analysis model. The offset value is only passed as a member attribute to the analysis.

Replacement profile name

Select a profile from the profile catalog. You can use different analysis profiles at the start and end of parts if the analysis application you use supports it.

To use different profiles at part ends, enter two profiles separated by a pipe character, for example: HEA120|HEA140

If the part is a built-up section in an analysis model, the name of the built-up section can be entered here. Any name can be entered, but if the name matches an existing catalog profile name, the physical properties of the section will be the same as the catalog profile properties.

Curved beam mode

Defines whether a beam is analyzed as a curved beam or as straight segments.

The options are:

  • Use model default

  • Use curved member

  • Split into straight segments

If you select Use model default, Tekla Structures uses the option selected from the Curved beams list in the Analysis Model Properties dialog box.

Use the advanced option XS_​AD_​CURVED_​BEAM_​SPLIT_​ACCURACY_​MM in File menu > Settings > Advanced Options > Analysis & Design to define how closely straight segments follow the curved beam.

No. of split nodes

Use to create additional nodes or analyze a beam as straight segments, for example, a curved beam.

Enter the number of nodes.

Split distances

To define additional nodes in the member, enter distances from the part starting point to the node.

Enter distances, separated by spaces, for example:

1000 1500 3000

Bar start number

Defines the start number for analysis bars.

Member start number

Defines the start number for analysis members.

Area attributes tab

Use the Area attributes tab in a plate’s (contour plate, concrete slab, or concrete panel) analysis properties dialog box to define the properties of its analysis elements.

You can use the options on this tab when the analysis class of the analysis part is Contour plate, Slab, or Wall.

Option

Description

Element type

The shape of the elements.

Rotation of local XY

Defines the rotation of the local xy plane.

Element size

x and y: The approximate dimensions of the elements, in the local x and y direction of the plate. For triangular elements, the approximate dimensions of the bounding box around each element.

Holes: The approximate size of the elements around openings.

Area start number

Defines the start number for the plate.

Simple area (ignore cuts etc)

Select Yes to create a simpler analysis model of the plate, where cuts and openings are not considered.

Smallest hole size to consider

Use to ignore small openings in the plate in the analysis.

Enter the size of the bounding box around the opening.

Supported

Not available with Tekla Structural Designer.

Use to define supports for a contour plate, concrete slab, or concrete panel.

You can create supports for the bottom edge of a panel, for all edge nodes of a slab or plate, or for all nodes of a beam. For panels, the bottom edge can be inclined.

The options are:

  • No

    No supports are created.

  • Simply (translations)

    Only translations are fixed.

  • Fully

    Both translations and rotations are fixed.

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