271083916 tekla-15-analysis-manual

Tekla Structures
Analysis Manual
Product version 15.0
January 2009
© 2009 Tekla Corporation

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TEKLA STRUCTURES 15 3
Contents
Preface ...............................................................................................................7
Audience ............................................................................................................................................................. 7
Additional help resources .................................................................................................................................... 7
Conventions used in this guide ........................................................................................................................... 8
Related guides .................................................................................................................................................... 9
1 Getting Started with Analysis................................................................. 11
1.1 Basics ................................................................................................................................................... 11
Following through structural analysis............................................................................................... 13
Members, elements, and nodes....................................................................................................... 13
1.2 Determining member properties ........................................................................................................... 14
Member analysis type ...................................................................................................................... 16
Member axis location ....................................................................................................................... 17
Analysis member offsets.................................................................................................................. 18
Analysis properties of plates ............................................................................................................ 18
Spanning ................................................................................................................................... 20
Loading ...................................................................................................................................... 20
Analysis offsets of plates ........................................................................................................... 21
Analysis properties of components.................................................................................................. 22
Analysis properties of slab components........................................................................................... 23
Analyzing composite beams ............................................................................................................ 24
Viewing analysis results ............................................................................................................ 25
Manual method - limitations ...................................................................................................... 25
Support conditions ........................................................................................................................... 25
Defining support conditions.............................................................................................................. 26
Design information ........................................................................................................................... 27
Properties of intermediate members................................................................................................ 28
Defining buckling lengths (columns) ................................................................................................ 29
Effective buckling length ............................................................................................................ 29
Kmode options .......................................................................................................................... 30
1.3 Fine-tuning analysis models ................................................................................................................. 31
Adding intermediate nodes .............................................................................................................. 34
Using rigid links................................................................................................................................ 35
1.4 Analysis information and settings ......................................................................................................... 37

4 TEKLA STRUCTURES 15
A closer look at the analysis model.................................................................................................. 37
Objects ....................................................................................................................................... 38
Nodes connecting members and elements ............................................................................... 38
Loads in analysis.............................................................................................................................. 39
Load modeling code......................................................................................................................... 39
Analysis method............................................................................................................................... 40
2 Loads........................................................................................................ 41
2.1 Basics.................................................................................................................................................... 41
Automatic loads and load groups..................................................................................................... 42
2.2 Grouping loads...................................................................................................................................... 42
Load group properties ...................................................................................................................... 43
Load group compatibility .................................................................................................................. 43
Working with load groups................................................................................................................. 44
Checking loads and load groups ............................................................................................... 45
Changing the load group ........................................................................................................... 45
Importing and exporting load groups ......................................................................................... 45
2.3 Load types and properties..................................................................................................................... 45
Load types........................................................................................................................................ 46
Load forms ....................................................................................................................................... 48
Load magnitude................................................................................................................................ 49
Temperature loads and strain .......................................................................................................... 49
2.4 Distributing loads................................................................................................................................... 49
Attaching loads to parts or locations ................................................................................................ 50
Applying loads to parts..................................................................................................................... 50
Loaded length or area ...................................................................................................................... 52
Modifying load distribution................................................................................................................ 52
2.5 Working with loads................................................................................................................................ 53
Changing loaded length or area....................................................................................................... 54
Scaling loads in model views ........................................................................................................... 54
Defining varying wind loads.............................................................................................................. 55
2.6 Load reference...................................................................................................................................... 56
Load Groups... ................................................................................................................................. 56
Create Point Load ............................................................................................................................ 58
Create Line Load.............................................................................................................................. 59
Create Area Load............................................................................................................................. 60
Create Uniform Load........................................................................................................................ 61
Create Temperature Load................................................................................................................ 62
Create Wind Load ............................................................................................................................ 63
3 Analysis and Design ............................................................................... 67

3.1 Analysis model geometry...................................................................................................................... 67
Creating rules to define analysis model geometry ........................................................................... 68
Modifying analysis model geometry................................................................................................. 70
Connecting or disconnecting parts in analysis................................................................................. 70
Defining analysis connections of parts............................................................................................. 71
Analysis part properties.................................................................................................................... 72
3.2 Analysis model properties..................................................................................................................... 74
Objects in an analysis model ........................................................................................................... 76
Analysis model filter .................................................................................................................. 77
Member axis..................................................................................................................................... 77
Member end connectivity................................................................................................................. 78
Defining nodes................................................................................................................................. 78
Model merging with analysis applications........................................................................................ 79
Analysis method............................................................................................................................... 80
Seismic analysis............................................................................................................................... 80
Modal analysis ................................................................................................................................. 81
Design codes and methods.............................................................................................................. 82
Design properties ...................................................................................................................... 82
Contents of STAAD.Pro results files and reports............................................................................. 82
3.3 Load combination ................................................................................................................................. 83
Load combination properties............................................................................................................ 83
Load combination factors................................................................................................................. 84
Load combination types ................................................................................................................... 84
Creating load combinations.............................................................................................................. 86
Automatic load combination............................................................................................................. 87
Automatically including loads in combinations................................................................................. 88
Manual load combination ................................................................................................................. 88
3.4 Working with analysis and design models............................................................................................ 89
Checking objects contained in an analysis model............................................................................ 90
Adding or removing analysis objects................................................................................................ 90
Showing analysis models and support conditions in model views................................................... 90
Analysis model status ...................................................................................................................... 93
Running analysis.............................................................................................................................. 93
Viewing analysis results................................................................................................................... 94
3.5 Analysis and design reference.............................................................................................................. 94
Analysis > Analysis & Design Models.............................................................................................. 95
New.................................................................................................................................................. 97
Add selected objects........................................................................................................................ 99
Remove selected objects............................................................................................................... 100
Load combinations......................................................................................................................... 100
Get results...................................................................................................................................... 101

View Analysis Parts........................................................................................................................ 102
Reset Geometry for Selected Parts................................................................................................ 102

Preface
Tekla Structures includes complete documentation in an accessible help system. Our online
help is a detailed guide to Tekla Structures concepts, tools, commands, and features, with
plenty of examples. The documentation is also available in PDF format.
Topics in the Preface are:
• Audience (p. 7)
• Additional help resources (p. 7)
• Conventions used in this guide (p. 8)
• Related guides (p. 9)
Audience
This guide is aimed at structural engineers, detailers and designers who model, analyze, and
design concrete and steel structures.
We assume that you are familiar with the processes of structural engineering.
Additional help resources
The following resources also provide information about Tekla Structures:
Web site http://www.tekla.com
E-mail Contact your local helpdesk via e-mail:
Area office E-mail address
China TeklaStructures.Support.CHI@Tekla.com
Finland TeklaStructures.Support.FI@Tekla.com

If you believe you have discovered a problem with this software, please report it to your Tekla
Structures Reseller using the maintenance request form provided at Help > Tekla on the
Web > Maintenance request....
Please send any comments or suggestions about Tekla Structures documentation to
BetC_Documentation@tekla.com.
Tekla Extranet Anyone with a current maintenance contract can use Tekla Extranet. Register now to get free
access to our online discussion forums, hints & tips, software downloads, tutorials, and more.
To register, go to https://extranet.tekla.com. You can also access Tekla Extranet from Tekla
Structures by clicking Help > Online Support > Tekla Extranet.
Conventions used in this guide
Typefaces We use different typefaces for different items in this guide. In most cases the meaning is
obvious from the context. If you are not sure what a certain typeface represents, you can check
it here.
Noteboxes We use several types of noteboxes, marked by different icons. Their functions are shown
below:
France TeklaStructures.Support.FR@Tekla.com
Germany TeklaStructures.Support.GER@Tekla.com
India TeklaStructures.Support.IN@Tekla.com
Japan TeklaStructures.Support.JPN@Tekla.com
Malaysia TeklaStructures.Support.MY@Tekla.com
Middle East TeklaStructures.Support.ME@Tekla.com
Sweden TeklaStructures.Support.SWE@Tekla.com
UK TeklaStructures.Support.UK@Tekla.com
US TeklaStructures.Support.US@Tekla.com
Area office E-mail address
Convention Usage
Bold Bold indicates the names of keyboard keys.
Bold is also used for general emphasis in text.
Arial bold Any text that you see in the user interface appears in Arial bold.
Items such as window and dialog box titles, field and button names,
combo box options, and list box items are displayed in this typeface.
Italic bold New terms are in italic bold when they appear in the current context
for the first time.
Monospace Extracts of Tekla Structures’s program code, HTML, or other
material that you would normally edit in a text editor, appears in
monospaced font.
Filenames and folder paths appear in monospace.
Also all the text you enter yourself appears in monospaced font.

Related guides
Tekla Structures includes a comprehensive help system in a series of online books. You will
also receive a printed installation guide with your Tekla Structures installation DVD.
• Modeling Manual
How to create a physical model.
• Analysis Manual
How to create loads and run structural analysis.
• Detailing Manual
How to create reinforcement, connections, and details.
• Drawing Manual
How to create and edit drawings.
• System Manual
Covers advanced features and how to maintain the Tekla Structures environment.
• TplEd User’s Guide
How to create and edit report and drawing templates.
• SymEd User’s Guide
A tip might introduce a shortcut, or suggest alternative ways of doing
things. A tip never contains information that is absolutely necessary.
A note draws attention to details that you might easily overlook. It can
also point you to other information in this guide that you might find
useful.
You should always read very important notes and warnings, like this
one. They will help you avoid making serious mistakes, or wasting your
time.
This symbol indicates advanced or highly technical information that
is usually of interest only to advanced or technically-oriented readers.
You are never required to understand this kind of information.

How to use the SymEd graphical interface to manipulate symbols.
• Installation Troubleshooting Guide
Printed booklet explaining how to install Tekla Structures.

Getting Started with Analysis
1 Getting Started with
Analysis
Introduction This chapter explains how to prepare a Tekla Structures model for structural analysis and
design. It includes a general description of the principles of analysis and design and discusses
the theoretical basis of the analysis method used in Tekla Structures. This chapter also explains
what is included in the analysis model, and how it is included. You will also learn how to
define support conditions for parts.
Audience This chapter is for engineers and designers who run structural analysis on concrete and steel
structures.
Assumed
background
We assume that you have created parts.
Contents This chapter is divided into the following sections:
• Basics (p. 11)
• Determining member properties (p. 14)
• Analysis information and settings (p. 37)
1.1 Basics
In this section This section presents the basic vocabulary and concepts we use to describe structural analysis
in Tekla Structures. The illustrations below show the analysis concepts and procedures.

Physical model A physical model includes the parts you have created using the Model Editor, and information
related to them. Each part in the physical model exists in the completed structure.
Load model The load model contains information about loads and load groups. It also contains information
about the building code Tekla Structures uses in load combination. To create a load model, see
Loads (p. 41).
Analysis model Tekla Structures generates an analysis model of the physical and load models when you run
structural analysis. Tekla Structures does the following in order to generate the analysis model:
• Creates nodes and analysis members and elements of the physical parts
• Determines the support conditions for nodes
• Determines the connectivity between the members and nodes
• Distributes loads to members and elements
The analysis model also includes load combinations.
Analysis
application
Tekla Structures links with a number of analysis applications and also supports import and
export with them in several formats. The analysis application you use to run structural analysis
uses data from the analysis model to generate analysis results.
For more information on the analysis applications that you can use with Tekla Structures, visit
Tekla Extranet at https://extranet.tekla.com. You can also access Tekla Extranet from Tekla
Structures at Help > Online Support > Tekla Extranet.
Parts
Loads
Physical and load models
Node
Loads
Analysis member
Analysis model

Topics Following through structural analysis (p. 13)
Members, elements, and nodes (p. 13)
Following through structural analysis
Before analysis Carry out the following steps before you run structural analysis in Tekla Structures:
1. Create the main load-bearing parts to form the physical model. See Parts. There is no need
to detail or create connections at this stage.
2. Set the support conditions for parts and connections, as well as other analysis properties
for individual members. See Determining member properties (p. 14).
3. Create the load model. See Loads (p. 41).
4. Define the analysis geometry settings and modify the geometry if needed. See Analysis
model geometry (p. 67) and Modifying analysis model geometry (p. 70).
5. Create a new analysis model and define its properties. See Analysis model properties (p.
74) and New... (p. 97).
6. Create load combinations. See Load combinations... (p. 100).
7. Check the analysis model in a Tekla Structures model view. See Showing analysis models
and support conditions in model views (p. 90) and Checking objects contained in an
analysis model (p. 90).
8. Check the analysis parts and modify their properties if needed. See Analysis part
properties (p. 72) and View Analysis Parts (p. 102).
Now you are ready to run the analysis.
See also The following sections discuss the theoretical basis of the analysis method used in Tekla
Structures. They also explain what is included in the analysis model, and how it is included.
• Members, elements, and nodes (p. 13)
• A closer look at the analysis model (p. 37)
• Loads in analysis (p. 39)
• Load modeling code (p. 39)
• Analysis method (p. 40)
Members, elements, and nodes
Members Every physical part (beam or column) that you select to include in the analysis model produces
one or more analysis members. A single physical part produces several members if the part
intersects with other parts. Tekla Structures splits the part at the intersection points of the
member axes.
Tekla Structures analyzes parts using properties in the profile and
material catalogs, including user-defined properties. If there are no
profile or analysis properties in the catalog, Tekla Structures calculates
them using the profile dimensions in the model.
To create accurate analysis models, make sure that connected parts have
common reference points, for example, at grid line intersections.

Elements Tekla Structures splits the plates, slabs, and panels that you include in the analysis model into
analysis elements, based on their analysis properties and the parts connected to them.
Nodes Nodes connect analysis members and elements. Tekla Structures creates nodes at:
• The ends of members
• The intersection points of member axes
• The corners of elements
The following properties affect the exact location of nodes:
• Part profiles, i.e. neutral axis and orientation
• Part reference lines (see Part position)
• Location of member axes (see Member axis location (p. 17) and Member axis (p. 77))
• Location and shape of elements (see Analysis properties of plates (p. 18))
• Node definition method (p. 78)
To force members to meet in the analysis model, Tekla Structures may need to merge nodes,
shift or extend member axes, create rigid links between nodes, ignore minor members, etc.
For more information on where and how Tekla Structures creates nodes, members, and
elements, see A closer look at the analysis model (p. 37).
See also Determining member properties (p. 14)
1.2 Determining member properties
You can define analysis properties for individual parts, or for an entire analysis model. This
section describes the properties of the individual analysis members. To define these, use the
Analysis, Loading, Composite, Start releases, End releases, and Design tabs in the part
properties dialog boxes, or the Analysis tab in the connection and detail dialog boxes.
The methods used to create a physical model affect the analysis model.
Because of this, you may need to try different modeling methods and
analysis model properties in order to create an accurate analysis model
of a complex physical model.

For more information on using common properties for the parts in an analysis model, see
Analysis model properties (p. 74).
Topics Member analysis type (p. 16)
Member axis location (p. 17)
Analysis member offsets (p. 18)
Analysis properties of plates (p. 18)
Analysis properties of components (p. 22)
Analysis properties of slab components (p. 23)
Analyzing composite beams (p. 24)
Support conditions (p. 25)
Defining support conditions (p. 26)
Design information (p. 27)
Properties of intermediate members (p. 28)
Defining buckling lengths (columns) (p. 29)
Fine-tuning analysis models (p. 31)
Some analysis properties of parts are user-defined attributes. For more
information, see Fine-tuning analysis models (p. 31).

Member analysis type
Use the Analysis tab in the part properties dialog boxes to define how Tekla Structures handles
individual members in the analysis. The following table lists the options.
You can have Tekla Structures show the member analysis type of parts using different colors in
the physical model. The Color column lists these colors.
Option Description Color
Default Member can take any type of load.
Columns, beams, and braces are
modeled as beam members. Slabs and
panels are modeled as shell elements.
Temperature load is available only for
beam members.
Light gray
Beam Member can take any load, including
temperature.
Dark red
Shell Member can take any load, except
temperature. Use to analyze slabs,
panels, and plates.
Magenta
Ignore Member ignored in the analysis. Red
Truss Member can only take axial forces, not
bending or torsion moments, or shear
forces. Usually used for brace members.
Green
Truss - Tension
only
Member can only take tensile axial
forces, not moments or shear forces. If
this member goes into compression, it is
ignored in the analysis.
Cyan
Truss -
Compression only
Member can only take compressive
axial forces, not moments or shear
forces. If this member goes into tension,
it is ignored in the analysis.
Yellow
Rigid diaphragm Only applies to contour plates and
concrete slabs parallel to the global xy
plane.
Nodes that belong to a part matching
the filter will be connected with rigid
links which together affect
displacement. For example, you can use
column_filter to connect only column
nodes to rigid diaphragms.
Blue
Shear wall For rectangular concrete panels and
concrete slabs using design codes ACI
and BS 8110 only.
Tekla Structures analyzes the concrete
panel or slab as a shear wall that does
not take any direct loads.
Gray
Plate Same as Shell but plate, membrane, or
mat foundation elements are used in the
analysis application.
Aqua
Membrane Lime
Mat foundation Pink

For more information on members with the Truss, Tension only, or Compression only
setting, see A closer look at the analysis model (p. 37).
To have Tekla Structures indicate the member analysis type of parts in an object group using
colors:
1. Click View > Representation > Object Representation....
2. Select the object group.
3. In the Color column, select Color by analysis type.
4. Click Modify.
For more information on object representation and object groups, see Object representation
settings and Object groups.
Member axis location
The locations of the member axes of parts define where the analysis members actually meet,
and their length in the analysis model. They also affect where Tekla Structures creates nodes.
See Members, elements, and nodes (p. 13) and A closer look at the analysis model (p. 37).
Use the Analysis tab in the part properties dialog boxes to define the member axis location of
individual parts for analysis purposes. The options are:
Tekla Structures uses the options above for each part when you select the Model default option
for the member axis location in the analysis model properties. See New... (p. 97) and Member
axis (p. 77).
The analysis application that you use may not support all options.
Option Description
Neutral axis The neutral axis is the member axis for this part.
The location of the member axis changes if the
profile of the part changes.
Reference axis The part reference line is the member axis for this
part. See also Part position.
Reference axis
(eccentricity by
neutral axis)
The part reference line is the member axis for this
part. The location of the neutral axis defines axis
eccentricity.
If you select the Neutral axis option, Tekla Structures takes the part
location and end offsets into account when it creates nodes. See End
offsets. If you select either of the Reference axis options, Tekla
Structures creates nodes at part reference points.

Analysis member offsets
Use offsets at the ends of analysis members to shorten or lengthen members in their local x
directions, for analysis purposes and to take the eccentricity effects into account.
For example, if a beam only actually spans the clear distance between two supporting columns,
you can use offsets to only include the clear distance in the analysis, instead of the distance
between the center points of the columns.
Another example is an eccentric connection between a precast concrete column and beam. To
take the eccentricity of the load from the beam into account, use the analysis offsets of the
beam.
Use the Analysis tab in the part properties or connection dialog boxes to define the offset at
each end of a member. The options are:
Analysis properties of plates
When creating an analysis model, Tekla Structures creates analysis elements for contour plates,
concrete slabs, and concrete panels.
Use the Analysis, Spanning, and Loading tabs in the appropriate part properties dialog boxes
to define how Tekla Structures creates analysis elements.
Option Description
Manual Works like end offsets for parts in the physical
model. Enter a positive or negative value in the Dx
field. See also End offsets.
Automatic Dx The offset is the distance between the intersection
of the parts’ neutral axes and the intersection of the
edges of the parts.
Longitudinal
member offset
Only applies to connection members and details.
Works like the Manual option and a value in the Dx
field for parts.

The analysis properties of plates are:
See also Spanning (p. 20)
Loading (p. 20)
Analysis offsets of plates (p. 21)
Design information (p. 27)
Property Description
Type See Member analysis type (p. 16). Set to Shell to
create elements in the analysis model.
Plane The plane of the plate on which Tekla Structures
creates the elements. The options are:
• Top plane
• Middle plane
• Bottom plane
• Left plane
• Right plane
• Middle plane (of left/right)
The reference points of connected parts must also
be in this plane.
Element size The approximate dimensions of the elements, in the
local x and y directions of the plate. For triangular
elements, the approximate dimensions of the
bounding box around each element.
Holes The approximate dimensions of the elements
around openings.
Some analysis properties of parts are user-defined attributes. For more
information, see Fine-tuning analysis models (p. 31).

Spanning
Use the plate spanning properties to define which parts carry loads from plates in slab-to-beam
connections and wall-to-column connections:
The spanning settings of the plate determine the spanning of the load. The spanning setting of
the load does not affect a load applied to a plate (see also Modifying load distribution (p. 52)).
Loading
The loading properties allow you to include concrete slabs as loads in the analysis model. The
loading properties are:
Spanning The options are:
Single spanning plates carry loads in the direction
of the primary axis. Beams or columns parallel to
the spanning direction are not connected to the
plate, and will not carry the load from plate.
Double spanning plates carry loads along the
primary and secondary axes. Beams or columns in
both directions will carry the load from plate.
Primary axis
direction
Define the direction of the primary axis in one of
the following ways:
• Enter 1 in the axis field which is parallel to the
primary axis direction.
• Click Parallel to part, and then select the
beam in the model that is parallel to the
direction.
• Click Perpendicular to part, and then select
the beam in the model that is perpendicular to
the direction.
Show direction on
selected members
A red line indicates the primary spanning direction
of the plate carrying the load.

Analysis offsets of plates
You can define analysis offsets for individual corners of contour plates, concrete slabs, and
concrete panels in the global x, y, and z directions. Use the Analysis offsets tab in the part’s
user-defined attributes dialog box. It includes Node offset fields for 12 corners.
To define analysis offsets for a plate:
1. Run the analysis, or create an analysis model.
2. Click Tools > Inquire > Object and select the plate in the model to query its corner points.
Generate self weight
load
The analysis model includes the part weight, for
example a deck, as a load even if the part is not
otherwise included in the analysis model.
If the part is included in the analysis model, so is its
self-weight. The option No works only with the
analysis types Ignore and Rigid diaphragm.
List boxes for
additional loads
Enter slab live load or additional self-weight
(screed, services) using three additional loads with
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 area load from a 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.

The Inquire Object dialog box opens, listing the corner indices and coordinates:
3. Double-click the plate in the model to open its properties dialog box.
4. On the Attributes tab, click the User-defined attributes... button to open the attributes
dialog box.
5. On the Analysis offsets tab, enter the x, y, and z offsets of each corner in the appropriate
field, according to the index of the corner. Use the current length units and separate the x,
y, and z values with spaces.
6. Click Modify.
Analysis properties of components
Use the Analysis tab in the connection or detail dialog boxes to define how Tekla Structures
handles connections and details in the analysis.
The analysis properties of connections and details are:
You can also modify analysis model geometry by moving analysis part
handles. See Modifying analysis model geometry (p. 70).

Analysis properties of slab components
Use the Analysis tab in the Slab generation with polygon plate (61) and Slab generation
with points (62) dialog boxes to define the analysis properties of parts created using these
components.
The following table lists the analysis properties of slab components. The option you select in
the Analysis type list box limits the other properties you can define (see the Only use for
column).
Use analysis
restraints
Set to Yes to use the analysis properties of the
connection or detail in the analysis, instead of the
analysis properties of the parts in the connection.
You must also select Yes in the Member end
release method by connection list box in the
Analysis Model Properties dialog box when you
create the analysis model. See Member end
connectivity (p. 78).
Member selection Use to associate the analysis properties with each
connection part (Primary, 1. secondary, 2.
secondary, etc.).
Restraint
combination
See Support conditions (p. 25) and Defining
support conditions (p. 26).
Support condition
Longitudinal
member offset
See Analysis member offsets (p. 18).
Analysis profile Tekla Structures uses this profile in the analysis,
instead of the one in the physical model, in order to
take the stiffness of the connection or detail into
account.
Analysis profile
length
This means that in the analysis, Tekla Structures
overrides the profile of the part in the physical
model, for this length.

Analyzing composite beams
Composite beams consist of a beam and studs, with a concrete slab on top of the beam. You can
define the analysis properties of the slabs in composite beams, and define the width of the slab
manually or automatically.
To define the properties of the concrete slab in a composite beam:
1. Open the Beam Properties dialog box and go to the Composite tab.
2. Select the Composite beam option in the Composite beam list box.
3. Select a Material and enter the Thickness of the slab.
Only use
for
Analysis type How Tekla Structures analyzes the slabs.
• Ignore: Slabs are not analyzed.
• Beam: Analyze each slab as a beam.
• Plate: Analyze each slab as a plate.
• Rigid diaphragm: Analyze slabs as a
rigid diaphragm.
See also Member analysis type (p. 16).
Beam axis The location of the beam axis. See also
Member axis location (p. 17).
Beam
Restraints The support conditions of beam ends. The
options are Pinned and Fixed.
Beam
Plate plane The plane on which to create the elements
and nodes. If you select Top plane, Tekla
Structures creates the elements on the top
surface of the slab.
Plate
Element type The shape of the elements. Plate
Element size x and y: The approximate dimensions of the
elements, in the local x and y direction of
the slab. For triangular elements, the
approximate dimensions of the bounding
box around each element.
Holes: The approximate size of the
elements around openings.
Plate
Filter Nodes that belong to a part matching the
filter will be connected to the rigid
diaphragm. For example, you can use
column_filter to connect only column
nodes to rigid diaphragms.
Rigid
diaphragm

4. To define the effective slab width:
• Manual method: Select the To the left from the beam and/or To the right of the
beam radio button and enter a value in the field next to these buttons. See also
Manual method - limitations (p. 25).
• Automatic method: For the left and right side, select the Automatic, half of span
length divided by radio button and enter a value in the field next to these buttons.
When you run the analysis, Tekla Structures calculates the effective slab width by
dividing the span length of the beam by the value you enter.
See also Viewing analysis results (p. 25)
Viewing analysis results
To view the analysis results for composite beams, right-click the beam and select Inquire on
the pop-up menu. The analysis results include:
• Element and node IDs
• Effective width
• Slab thickness
• Slab material
• Concrete strength
• Rib width and height
• Stud diameter and length
Manual method - limitations
• Effective width cannot exceed the distance to the nearest beam.
• Effective width cannot be more than half the distance to the nearest composite beam.
• If there is no beam on either side of the composite beam, the slab width is zero. Use the
Automatic composite beam option to have Tekla Structures calculate the slab width.
Support conditions
In structural analysis, the stresses and deflections of a part depend on how it is supported by, or
connected to, other parts. You normally use restraints or springs to model connections. These
determine how analysis members move, deflect, warp, deform, etc., in relation to each other, or
to nodes.
Member ends and nodes have degrees of freedom (DOF) in three directions. The displacement
of a member end can be free or fixed, and the rotation can be pinned or fixed. If the degree of
connectivity is between free, or pinned, and fixed, use springs with different elastic constants to
model them.
Tekla Structures uses part, connection, or detail properties to determine how to connect
members in the analysis model. To define the member end conditions, use the Start releases
and End releases tabs in the part properties dialog boxes. The connection and detail dialog
boxes have Analysis tabs.
The analysis properties of a member determine the degrees of freedom for each end of a main
part or member. The first end of a part has a yellow handle, the second end has a magenta
handle. See also Part position.
See also Defining support conditions (p. 26)
Determining member properties (p. 14)

Defining support conditions
Parts Use the Start releases and End releases tabs in the part properties dialog boxes to define
support conditions. The Start releases tab relates to the first part end (yellow handle), the End
releases tab to the second part end (magenta handle).
Plates To define the support conditions of contour plates, concrete slabs, and concrete panels, use the
Supported list box in the Analysis Part Properties dialog box.
Connections and
details
Use the Analysis tab in the connection or detail dialog boxes to define the support conditions
for the members and node in a connection. Use the Member selection list box to associate the
support conditions with each connection part (Primary, 1. secondary, 2. secondary, etc.).
Support
conditions
Tekla Structures includes four predefined combinations for member ends, and an option for
user-defined settings. The predefined combinations (the first four in the following table)
automatically set the appropriate support conditions and degrees of freedom. The combinations
are:
The support conditions of a member end can be:
Combinatio
n
Support
condition
Translational
DOFs
Rotational
DOFs
Supported Fixed Fixed
Supported Fixed Pinned
Connected Fixed Fixed
Connected Fixed Pinned
Use this option to define your own settings for the supports
and connections at member ends. You can use springs and
almost any combination of degrees of freedom.
To ensure that the part remains stable, and that all loads applied to it pass
through to the other structures, avoid using combinations with too many
degrees of freedom.

Displacements
and rotations
’U’ denotes translational degrees of freedom (displacement). ’R’ denotes rotational degrees of
freedom (rotation). Define the degrees of freedom in the global coordinate system. The options
are:
See also Support conditions (p. 25)
Determining member properties (p. 14)
Analysis part properties (p. 72)
Design information
Use the Design tab in the part properties dialog boxes to view and modify the design properties
of individual parts in an analysis model. Design properties are properties which can vary,
according to the design code and the material of the main part (for example, design settings,
factors, and limits).
Option Description
Connected Member end is connected
to an intermediate analysis
node (another part).
Indicate degrees of
freedom for the node.
Supported Member 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.
Option More information
Free Only applies to translational degrees of freedom.
Pinned Only applies to rotational degrees of freedom.
Fixed
Spring Enter translational and rotational spring constants.
The units Tekla Structures uses depend on the
program’s unit settings.
Partial release Only applies to rotational degrees of freedom.
Use to specify the degree of connectivity, if it is
between fixed and pinned. Enter a value between 0
(fixed) and 1 (pinned).

The properties you see when you first open the dialog box are the properties that apply to the
entire analysis model you have selected in the Analysis & Design Models dialog box. See also
Design codes and methods (p. 82).
To set different design properties for specific parts, modify the values in the appropriate part
properties dialog box.
For example, if the analysis model contains parts with different material grades, define the
most common material grade using the analysis model properties. Then change the material
grade of specific parts using the appropriate part properties dialog box.
To omit individual members from the design check when you run the analysis, set the
following properties to No:
• Steel parts: Check design - Enable design check of member
• Concrete parts: Calculate required area - Enable design check of member
Properties of intermediate members
When creating an analysis model, Tekla Structures may need to produce more than one
analysis member for each physical part. This can result in intermediate members and member
ends.
Tekla Structures determines the analysis properties of intermediate members as follows:
1. The member analysis type and member axis location of the analysis members are the same
as of the original part.

2. The analysis offsets of the part ends apply to the corresponding analysis member ends.
Intermediate member ends do not have analysis offsets.
3. The support conditions of all intermediate member ends are Connected. The translational
and rotational degrees of freedom are all Fixed. This reflects the nature of the physical
part, which is a continuous length.
4. The effective buckling length of each analysis member is K*L. K is the length factor for
buckling. L is length, a value described by the Kmode design property. For more
information, see Defining buckling lengths (columns) (p. 29).
5. The other design properties are the same for the analysis members as for the original part.
Defining buckling lengths (columns)
Tekla Structures allows you to define buckling lengths for column segments, which represent
the building levels. Tekla Structures automatically divides columns into segments at the point
where a support in the buckling direction exists, or where the column profile changes.
See also Effective buckling length (p. 29)
Kmode options (p. 30)
Effective buckling length
Effective buckling length is K*L, where K is the length factor and L is the buckling length. To
calculate a part’s effective buckling length:
1. Open the part properties dialog box and go to the Design tab.
2. Select an option for Kmode. For more information about the available options, see Kmode
options (p. 30).
3. Enter one or more values in the K - Length factor for buckling field. The number of
values you can enter depends on the option you selected in the Kmode field. For multiple
values:
• Enter a value for each column segment starting with the lowest segment, and
• Use spaces to separate multiple values:
• You can also use multiplication to repeat factors, for example, 3*2.00.
4. Go to the L - Buckling length field:
• To automatically calculate length values, leave the fields blank.
• To override one or more length values, enter values in the relevant buckling length
fields. The number of values you need to enter depends on the option you selected in
the Kmode field. You can use multiplication to repeat buckling lengths, for example,
3*4000.
5. Create the analysis model and use the Tools > Inquire > Object command on a part. The
Inquire Object dialog box opens and displays the member number and the effective
buckling length for each segment:

Kmode options
Use the Kmode options to define how Tekla Structures calculates buckling lengths. The
options are:
Option Description
Physical member L is the length of the column.
Column segment L is the length of one column segment.
Column segment,
multiple values
L is the length of one column segment with
user-defined factors and lengths for each
column segment.
Analytical member L is the length of the member in the analysis
model.
Analytical member,
multiple values
L is the length of the member in the analysis
model with user-defined factors and lengths for
each member.

1.3 Fine-tuning analysis models
Several properties and user-defined attributes enable you to control how Tekla Structures
creates analysis models.
To modify the user-defined attributes, open the part properties dialog box and click the User-
defined attributes... button to open the attributes dialog box.
You can also modify several properties on the Analysis and Analysis (2) tabs of the attributes
dialog box:
Use the analysis model geometry settings and analysis properties of parts
to define how Tekla Structures creates analysis models. See Analysis
model geometry (p. 67) and Analysis part properties (p. 72).

Attribute Description Options/Values
Node offsets Moves the part in the analysis
model when members do not
meet and are not connected.
Consider
longitudinal model
offsets
Controls the member
longitudinal offsets.
Auto (default) uses the Dx end
offset if it extends the beam, or if
it shortens the beam and there is
a node near the shortened
position.
None
Extending only uses the Dx end
offset when it extends the beam,
and ignores it when it shortens
the beam.
Always
No. of split nodes Use to create additional nodes or
analyze a beam as straight
segments, for example, a curved
beam.
See also Adding intermediate
nodes (p. 34).
Enter the number of nodes.
Split distances To define additional nodes in the
member, enter distances from
the part starting point to the
node.
See also Adding intermediate
nodes (p. 34).
Enter distances, separated by
spaces, for example:
1000 1500 3000
Curved beam by
straight segments
Use to analyze a curved beam as
straight segments.
Yes
No
Node merge
distance
Merges nodes within the
distance specified into a single
node.
For example, use this to force
truss-type analysis members to
meet in the analysis model.
The Keep axis attribute
overrides this attribute.
Distance
Design group
(optimization)
Defines which design group the
part belongs to. Used in
optimization.
Member level (z) Sets the same z coordinate for all
nodes.
Enter a value for the z
coordinate.

Profile Analysis part profile.
You can use different analysis
profiles at the start and end of
parts if the analysis application
you use supports it.
Select a profile from the profile
catalog.
To use different profiles at part
ends, enter two profiles
separated by a pipe character, for
example:
HEA120|HEA140
Connect to (part
IDs)
Forces or disables connections
between the analysis members
you specify.
Works with the Connect
exclusively attribute.
To enable connections, enter the
part ID’s, separated by spaces.
To prevent connection, enter
negative part ID’s, separated by
spaces.
Connect exclusively Select Yes to connect the part
only to the parts defined by the
Connect to (part IDs) attribute.
Keep axis Select Yes to fix the location of
member axis so that Tekla
Structures does not shift the axis
when it makes members meet in
the analysis model.
For example, use this with the
Node merge distance attribute
to force truss-type members to
meet in the analysis model.
Overrides the Node merge
distance attribute.
Rigid link Enables or disables rigid links at
the start, mid, and end points of
parts.
Use with the Force to centric
connection option in the
Analysis Model Properties
dialog box to specify which
parts to use rigid links.
See also Using rigid links (p.
35).
For each point:
0 = disable
1 = enable
For example:
• 0 = no rigid links
• 100 = rigid link at start point
• 111 = rigid links at start,
mid, and end point
• 001 = rigid link at end point
Pinned rigid link (to
part names)
Connects the part using pinned
rigid links to the parts you
specify.
Enter the part names, separated
by spaces, commas, or
semicolons. You can also use
wildcards (see Wildcards).
Thickness Analysis plate thickness.
Minimum hole size
(to consider)
Use to ignore small openings in
plates in the analysis.
Enter the size of the bounding
box around the opening.
Short cantilever
limit (to remove)
Use to ignore short plate
cantilevers in the analysis.
Enter a cantilever length.

See also To find out how to create user-defined attributes, see Adding properties.
A closer look at the analysis model (p. 37)
Analysis offsets of plates (p. 21)
Adding intermediate nodes
Sometimes intermediate nodes are needed along a member, for example in frequency analysis.
To create additional nodes, use the following user-defined attributes on the Analysis tab of the
part properties dialog box:
Mesh point IDs
(add/remove)
Use to exclude nodes from or
include nodes in plate element
meshes.
Only nodes created because of
connected members or loads can
be excluded.
To include nodes, enter the point
ID’s, separated by spaces.
To exclude nodes, enter negative
point ID’s.
For example:
1203 -1205 -1206
Simple plate Select Yes to create a simpler
analysis model of plates, where
cuts and openings are not
considered.
Trim plate
connections
Select No to connect plates using
rigid links, without moving
nodes.
Select Yes to connect plates by
moving plate nodes, instead of
using rigid links.
Supported Use to define supports for plates
and beams.
You can create supports for the
bottom edge of a wall, for all
edge nodes of a slab, or for all
nodes of a beam. For walls the
bottom edge can be inclined.
Simply: only translations are
fixed
Fully: both translations and
rotations are fixed
Some attributes are only available if you select the Extended clash
check checkbox in the Analysis Model Properties dialog box. They
are:
• Rigid link
• Node merge distance
• Connect to (part IDs)
• Connect exclusively
• Keep axis
For more information on the Extended clash check, see Creating
common nodes (p. 38).

• No. of split nodes
Enter the number of nodes. Tekla Structures gives equal spacing to added nodes.
• Split distances
Enter the distance values from the part starting point. Tekla Structures adds nodes using
these distances:
Using rigid links
You can enable or disable rigid links using the Node definition method (p. 78) in the entire
analysis model. You can override this setting in specific places:
• If Node definition is Force to centric connection, rigid links are generally not used, but
it is possible to force rigid links in specific places.
• If Node definition is Use rigid links, rigid links are used, but it is possible to prevent the
use of rigid links in specific places.

To define rigid links, use the user-defined attribute Rigid link in the part properties.
The value of the attribute is a three-digit number of 1’s and/or 0’s.
• 1 = rigid link enabled
• 0 = rigid link disabled
The first digit is the setting for the part start point, the second digit is the setting for all
intermediate points between the start and end point, and the third digit is setting for the part end
point.
A rigid link is created at a connection between two members if:
• An eccentric connection exists.
• Rigid links are enabled for both parts, either as an analysis model property or user-defined
attribute of parts.
Example 1 The node definition method of the analysis model is Force to centric connection. If the Rigid
link attribute is not set, there will be no rigid link. To create the rigid link, use the following
values of the user-defined attribute Rigid link:
If you are merging nodes of two parts, and you have set the Keep axis
attribute to Yes for both parts, Tekla Structures creates a rigid link.

Example 2 The node definition method of the analysis model is Use rigid links. If the Rigid link attribute
is not set, there will be rigid links. To disable rigid link between two members, set the attribute
for one part only:
1.4 Analysis information and settings
This section generally discusses the analysis process and describes analysis settings.
Topics A closer look at the analysis model (p. 37)
Loads in analysis (p. 39)
Load modeling code (p. 39)
Analysis method (p. 40)
A closer look at the analysis model
This section gives detailed information on how Tekla Structures creates analysis models of
physical models.
For this beam, type in 010. (Rigid link is wanted in mid beam.)
For this brace, type in 100. (Rigid link is wanted at beam start point.)
For this beam, type in 101. (No rigid link is created for intermediate
nodes.)

See also Objects (p. 38)
Nodes connecting members and elements (p. 38)
Objects
Tekla Structures ignores the following objects in the analysis, even if you have included them
in the analysis model (see Objects in an analysis model (p. 76)):
• Parts and loads that are filtered out (see Analysis model filter (p. 77))
• Component objects (minor parts, bolts, reinforcing bars, etc.)
• Parts with the Ignore setting (see Member analysis type (p. 16))
Truss members Tekla Structures does not split members with the Truss, Tension only, or Compression only
setting (truss members) when two or more truss members intersect with a normal member or
with another truss member.
To force truss member nodes to meet at the same point, use the user-defined attributes Node
merge distance and Keep axis. For more information on user-defined attributes, see Fine-
tuning analysis models (p. 31).
Nodes connecting members and elements
Tekla Structures first creates analysis nodes:
• On member axes at the ends of parts
• At the intersection points of member axes
• At the corners of elements
Tekla Structures then checks if the analysis members have common nodes.
Creatingcommon
nodes
To force Tekla Structures to find parts that clash and create common nodes for them, select
Extended clash check checkbox in the Analysis Model Properties dialog box.
If the end points of the parts are within 10 mm of each other, Tekla Structures moves the nodes
in the following order:
1. Horizontal parts
2. Other parts
Vertical parts and parts that have the user-defined attribute Keep axis set to Yes do not move.
Also, supported nodes are not moved.
If the part end points are not within 10 mm of each other, Tekla Structures extends each part’s
bounding box by 1 mm to find parts that clash.
Other methods Tekla Structures also creates common nodes for members if:
• A connection exists between the members.
• The user-defined attribute Connect to (part IDs) forces the parts to meet.
See also • For more information on user-defined attributes, see Fine-tuning analysis models (p. 31).
• For more information on the nodes, see Defining nodes (p. 78).
Element nodes This is how Tekla Structures creates nodes when plates connect with other parts:
The methods used to create a physical model affect the analysis model.
Because of this, you may need to try different modeling methods and
analysis model properties in order to create an accurate analysis model
of a complex physical model.

Loads in analysis
These are the principles that Tekla Structures follows when it processes loads in the physical
model to create analysis model loads.
You define which loads are included in the analysis model. Tekla Structures applies these loads
to members and elements, based on each load’s part name or selection filtering criteria,
bounding box, and load panel properties. See Applying loads to parts (p. 50) and Modifying
load distribution (p. 52).
In load decomposition, the parts to which a load is applied are projected to the load plane. The
load is then applied to these parts according to the load panel properties, of which the load’s
spanning properties and distance from each part are most important.
Point loads A point load is applied to the nearest node, or member or element location. If the point load is
not located directly on any of these, it may either snap to the nearest location or it may be split
into several loads, depending on the filtering criteria, bounding box, and load panel properties.
Line loads A line load is transferred to members and elements that are inside the bounding box of the line
load, and that match the part name or selection filtering criteria of the load. In special cases the
line load may be decomposed to point loads if it is not perpendicular to the part it is applied to.
If several members receive the load, the load is distributed based on the length of each member
and the distance between the load and member.
Area and uniform
loads
Area loads are decomposed to line loads, and in special cases to point loads if they are not
perpendicular to the part they are applied to. These decomposed loads are then applied to
members and elements. Members inside the bounding box of the load and that match the part
name or selection filtering criteria receive the load. Load panel properties, especially single or
double spanning and spanning direction, also affect load decomposition.
Nodal load Tekla Structures binds loads to nodes or members in the analysis model. A load is a nodal load
if:
• It is between two nodes and the distance to the nearest node is less than 110 mm.
• It is not between two nodes (even outside the member) but inside the bounding box and
meets the part name or selection filtering criteria.
Nodal loads do not cause parts to bend.
Member load If a load does not meet the criteria for the nodal load, it is a member load. Member loads lie
along the length of the member and cause member deformations.
Other loads Temperature loads are like line loads which affect an entire member. The left, right, top, and
bottom surfaces of the member a temperature load affects define the direction of the load.
Load modeling code
Use the Options dialog box to determine the building code and safety factors Tekla Structures
uses in load combination.
Connected part Action
Beam Tekla Structures splits the beam and creates nodes in it
at the element corners.
Column Tekla Structures creates a node at the column.
Another plate Tekla Structures creates the analysis elements so that
the plates have common nodes on the edges of the
plates.

1. Click Tools > Options > Options... > Load modeling.
2. Go to the Current code tab.
3. Select the code in the Load modeling code list box.
4. Change load combination factors on the appropriate tab if needed:
5. Click OK.
Analysis method
You can use either the linear (first order), or non-linear (second order, P-delta), analysis
method in Tekla Structures. The non-linear method considers the non-linear nature of the
geometry. This takes into account major deflections, but not the non-linear nature of materials.
Tekla Structures treats materials as linear. See also Analysis method (p. 80).
Tab Description More information
Current code The code to follow in analysis
and load combination.
Eurocode The partial safety factors in limit
states and reduction factors, for
the Eurocode, based on load
group types.
Load combination
factors (p. 84)
British The partial safety factors in limit
states, for the British code, based
on load group types.
AISC (US) The partial safety factors in limit
states, for the US code, based on
load group types.
UBC (US) Uniform building code,
American code.
CM66 (F) The partial safety factors in limit
states, for the French code for
steel structures, based on load
group types.
BAEL91 (F) The partial safety factors in limit
states, for the French code for
concrete structures, based on
load group types.
IBC (US) International building code.
American code.
ACI American Concrete Institute
publication 318.
If you have to change the code during a project, you will also need to
change the load group types and check load combinations.

Loads
2 Loads
Introduction Once you have modeled physical structures by creating parts you can start adding loads. In
Tekla Structures, you can create point loads, line loads, area loads with uniform or variable
distribution. You can also model temperature, wind, and seismic loads. Either attach loads to
specific parts or to locations.
In this chapter This chapter explains how to create and group loads. It also includes a general description of
load groups, load types, and load properties. Load reference (p. 56) contains step-by-step
instructions for all load commands.
Assumed
background
We assume that you have created a Tekla Structures model and have a basic understanding of
modeling.
Contents This chapter is divided into the following sections:
• Basics (p. 41)
• Grouping loads (p. 42)
• Load types and properties (p. 45)
• Distributing loads (p. 49)
• Working with loads (p. 53)
• Load reference (p. 56)
2.1 Basics
This section presents some Tekla Structures vocabulary and concepts to help you start to model
loads.
Load model A load model is the portion of the Tekla Structures model that includes all loads, together with
the load group and building code information related to them. Each load in a load model has to
belong to a load group. Each load can only belong to one load group. A load group can contain
one or more loads.
Load group A load group is a set of loads that are treated alike during load combination. Load groups
should contain loads caused by the same action and to which you want to refer collectively.
Tekla Structures assumes that all loads in a group:
• Have the same partial safety and other combination factors

Loads
• Have the same action direction
• Occur at the same time and all together
See Grouping loads (p. 42) and Load combination (p. 83).
You need to create load groups because the same action can cause different types of loads, for
example, point loads and area loads. See Load types (p. 46). You can include as many loads as
you like in a load group, of any load type.
Working with
loads
In Tekla Structures, you can attach each load to a part for modeling purposes. You can also
create floating loads that are bound to locations rather than parts. See Attaching loads to parts
or locations (p. 50).
Use the load’s bounding box and part name filter or a selection filter to define which parts carry
the load. See Applying loads to parts (p. 50).
Topics Automatic loads and load groups (p. 42)
Automatic loads and load groups
Self-weight Tekla Structures automatically calculates the self-weight of structural parts using the density of
the material and the dimensions of the part.
To automatically include the self-weight of parts in load combinations, select the Include self-
weight checkbox when you create load combinations. See Creating load combinations (p.
86).
Wind loads Use the Wind load generator (28) tool to define the effects of wind on a structure. See Create
Wind Load (p. 63).
Seismic loads To automatically include seismic loads in the x and y directions in load combinations:
1. Define the code to follow in the seismic analysis.
2. Define the load groups to include in the seismic analysis and their factors.
For more information, see Seismic analysis (p. 80).
See also Load combination types (p. 84)
Attaching loads to parts or locations (p. 50)
2.2 Grouping loads
Load groups should contain loads caused by the same action and to which you want to refer
collectively. Tekla Structures assumes that all loads in a group:
• Have the same partial safety and other combination factors
• Have the same action direction
• Occur at the same time and all together
Topics Load group properties (p. 43)
Load group compatibility (p. 43)
Working with load groups (p. 44)

Loads
Load group properties
To define the properties of a load group, click the Load groups icon on the Loads and
Analysis toolbar to open the Load Groups dialog box. The properties are:
Current When you apply loads in the model, Tekla Structures applies the Current load group. You can
only define one load group as Current.
Name Each load group must have a unique name. Use load group names to define the visibility and
selectability of loads. For example, you can select, modify, or hide loads based on their load
group. See Filtering objects.
Type The type of a load group is the type of action that causes the loads.
Actions causing loads are building code specific. See Load modeling code (p. 39). Most
building codes use some or all of the following actions and load group types:
• Permanent, dead, and/or prestressing loads
• Live, imposed, traffic, and/or crane loads
• Snow loads
• Wind loads
• Temperature loads
• Accidental and/or earthquake loads
• Imperfection loads
Direction The direction of a load group is the global direction of the action that causes the loads.
Individual loads in a load group retain their own magnitudes in the global or local x, y, and z
directions. See also Load magnitude (p. 49).
Load group direction affects which loads Tekla Structures combines in load combination:
• z direction groups are combined with both x and y direction groups.
• x or y direction groups are not combined with each other.
Color Use different colors for different load groups.
See also Load Groups... (p. 56)
Load group compatibility (p. 43)
Load group compatibility
When Tekla Structures creates load combinations for structural analysis, it follows the building
code you select in Tools > Options > Options... > Load modeling. See Load modeling code
(p. 39) and Load combination (p. 83).
To accurately combine loads which have the same load group type, you need to identify which
load groups:
• Can occur at the same time (are compatible)
• Exclude each other (are incompatible)
Tekla Structures automatically determines and applies the self-weight of
parts. See Automatic loads and load groups (p. 42).

Loads
To define load group compatibility, click Load groups icon on the Loads and Analysis
toolbar to open the Load Groups dialog box. Enter numbers to indicate compatibility.
Compatibility Compatible load groups can act together or separately. They can actually be one single loading,
for example, a live loading that needs to be split in parts acting on different spans of a
continuous beam. Tekla Structures then includes none, one, several, or all of the compatible
load groups in a load combination.
Incompatibility Incompatible load groups always exclude each other. They cannot occur at the same time. For
example, a wind loading from the x direction is incompatible with a wind loading from the y
direction. In load combination Tekla Structures only takes into account one load group in an
incompatible grouping at a time.
Working with load groups
Use the Load groups dialog box to view, define, modify, and delete load groups. For example,
this is where you set load group properties and indicate load group compatibility.
Click the Load groups icon on the Loads and Analysis toolbar to open the dialog box:
Tekla Structures automatically applies basic compatibility facts, such as
self-weight being compatible with all other loads, or live loads being
compatible with wind load.
Tekla Structures does not combine loads in the x direction with those in
the y direction.
Compatibility indicators are all 0 by default. It indicates that Tekla
Structures combines the load groups as defined in the building code.
Load group types vary according to the code defined in Tools > Options
> Options... > Load modeling. If you have to change the code during a
project, you will also need to change the load group types and check load
combinations.

Loads
Checking loads and load groups
To find out which load group a load belongs to, select the load in the model and click the Load
groups by loads button. Tekla Structures highlights the load group in the dialog box.
To find out which loads belong to a load group, select the load group in the dialog box and
click the Loads by load groups button. The associated loads are highlighted in the model.
If you have many loads in the model, you can show the group name and magnitude in the
model view by right-clicking a load and selecting Inquire from the pop-up menu. If you have
already run the analysis, Tekla Structures also highlights the parts that carry this load.
Changing the load group
To move a load to a different load group, select the load in the model, then select a load group
in the dialog box and click the Change load group button.
Importing and exporting load groups
To use the same load groups in other models, you can import and export load groups.
• Right-click on a load group in the Load Groups dialog box and select Export... from the
pop-up menu to allow the load group to be used in other models.
• Right-click on the load group list in the Load Groups dialog box and select Import... from
the pop-up menu to use load groups from another model.
Tekla Structures saves the load group files in the folder you specify, with the extension lgr.
The default load groups are defined in the DefaultLoadGroups.lgr file, located in the
...TeklaStructures*version*environments*your
environment*system folder.
2.3 Load types and properties
Introduction Each load has a type and properties which define it (e.g. magnitude, direction, and distribution).
This section describes the different load types and the properties of each load type.
Use the load properties dialog box to view or modify the properties of a load. Click Analysis >
Properties and select a load type to open its properties dialog box.

Loads
Filtering by
properties
You can use load types and groups in filters. For example, you can select, modify, or hide loads
based on their type and load group. See Filtering objects.
Topics Load types (p. 46)
Load forms (p. 48)
Load magnitude (p. 49)
Temperature loads and strain (p. 49)
See also Grouping loads (p. 42)
Distributing loads (p. 49)
Load types
Tekla Structures includes the following load types:

Loads
Uniform load
Area load
Point load
Line loads
Load type Description
Point load A concentrated force or bending moment that
can be attached to a part.
Line load A linearly-distributed force or torsion. By
default it runs from a point to another point.
You can also create a line load with offsets
from the points. A line load can be attached to a
part. Its magnitude can vary linearly across the
loaded length.
Area load A linearly-distributed force bounded by a
triangle or quadrangle. You do not have to bind
the boundary of the area to parts. Area loads
can have openings.
Uniform load A uniformly-distributed force bounded by a
polygon. Uniform loads can have openings.
You do not have to bind the polygon to parts.

Loads
Load forms
Distributed loads (line and area loads) can have different load forms.
Line load The load form of a line load defines how the load magnitude varies along the loaded length.
The options are:
Area load The load form of an area load defines the shape of the loaded area. It can be:
Temperature load • A uniform change in temperature, that is
applied to specified parts, and that causes
axial elongation in parts.
• A temperature difference between two
surfaces of a part that causes the part to
bend.
Strain An initial axial elongation or shrinkage of a
part.
To ensure that load analysis is correct, use area and uniform loads for
loads on floors. For example, when the layout of beams changes, Tekla
Structures recalculates the loads to the beams. It will not do this if you
use point or line loads on individual beams.
Load type Description
Option Description
The load magnitude is uniform across the loaded
length.
The load has different magnitudes at the ends of the
loaded length. The magnitude changes linearly
between the ends.
The load magnitude changes linearly, from zero at
the ends of the loaded length, to a fixed value in the
middle of the loaded length.
The load magnitude changes linearly, from zero at
one end of the loaded length, through two
(different) values, back to zero at the other end.
Option Description
Quadrangular
Triangular

Loads
For information on how to define the length or area a load affects, see Loaded length or area
(p. 52).
See also Load magnitude (p. 49)
Load magnitude
Load magnitude can occur in x, y, and z directions. The coordinate system is the same as the
current work plane, so positive coordinates indicate a positive load direction. See Work plane.
For example, when you create loads perpendicular to sloped parts, shifting the work plane
helps you to place loads accurately. See Defining the work area.
Some types of loads can have several magnitude values. For example, the magnitude of line
loads may vary along the loaded length. See Load forms (p. 48).
In the load properties dialog boxes, the following letters denote magnitudes of different types:
• P is for a force acting on a position, along a line, or across an area.
• M is for bending moments acting on a position or along a line.
• T is for torsional moments acting along a line.
Temperature loads and strain
Temperature loads can be caused by:
• An increase or decrease in temperature
• A difference in temperature between the top and bottom surfaces of a part
• A difference in temperature between the sides of a part
Temperature changes cause axial elongation or uniform volume expansion in parts.
Different surface temperatures cause parts to bend.
Strain Strain is an initial axial elongation (+) or shrinkage (-) of a part.
To define the temperature loads and strain that affect parts, click Analysis > Properties >
Temperature Load... and use the Magnitude tab.
See also Create Temperature Load (p. 62)
2.4 Distributing loads
This section explains how to attach loads and how to define which parts, or lengths and areas of
parts, carry loads.

Loads
Topics Attaching loads to parts or locations (p. 50)
Applying loads to parts (p. 50)
Loaded length or area (p. 52)
Attaching loads to parts or locations
You can attach loads to parts or locations for modeling purposes.
Attaching a load to a part binds the load and the part together in the model. If the part is moved,
copied, deleted, etc., it affects the load. For example, a prestressing load moves with the part to
which it is attached, and disappears if the part is deleted.
If you do not attach a load to a part, Tekla Structures fixes the load to the position(s) you pick
when you create the load.
To attach a load to parts or locations, open the load properties dialog box. On the Distribution
tab, select an option in the Load attachment list box:
To define which parts carry a load, see Applying loads to parts (p. 50).
Applying loads to parts
In order to apply loads in the structural analysis model, Tekla Structures searches for parts in
the areas that you specify. For each load, you can define the load-bearing parts by name or
selection filter, and the search area. To do this, open the load’s properties dialog box and click
the Distribution tab.
Option Description
Attach to member Attaches the load to a specific part. If the part is
moved, copied, deleted, etc., it affects the load.
Don’t attach The load is not attached but it is considered a
floating load. This load is bound to the position
you pick when you create the load, not to parts.
If you select the Attach to member option, you must select the part
before picking the position for the load.

Loads
Load-bearing
parts
To define the load-bearing parts by name:
1. In the Load-bearing parts list box:
• Select Include parts by name to define the parts that carry the load.
• Select Exclude parts by name to define the parts that do not carry the load.
2. Enter the part names.
To define the load-bearing parts by selection filter:
1. In the Load-bearing parts list box:
• Select Include parts by filter to define the parts that carry the load.
• Select Exclude parts by filter to define the parts that do not carry the load.
2. Select the selection filter in the second list box.
For more information on selection filters and filtering, see Filtering objects.
Bounding box Use the load’s bounding box to define the area to search for the parts that carry the load. The
bounding box is the volume around the load that Tekla Structures searches for load-bearing
parts.
Each load has its own bounding box. You can define the dimensions of a bounding box in the x,
y, and z directions of the current work plane. The dimensions are measured from the reference
point, line, or area of the load. See also Handles (p. 54).
Offset distances from the reference line or area do not affect the size of the bounding box. See
Loaded length or area (p. 52).
See also Each load’s load panel properties also affect which parts receive the load. See Modifying load
distribution (p. 52).
You can use wildcards when listing the part names. See Wildcards.

Loads
Loaded length or area
If a line, area, or uniform load affects a length or area which is difficult to pick in the model,
pick one close to it. Then use the values in the Distances fields in the load properties dialog
boxes to pinpoint the length or area. You can shorten or divide the loaded length, and enlarge or
reduce the loaded area.
Line load To shorten or divide the length of a line load, enter positive values for a and b.
Area load To enlarge the area an area load affects, enter a positive value for a. To reduce the area, enter a
negative value.
Modifying load distribution
By default, Tekla Structures distributes loads using the panel method. To modify the way loads
are distributed, modify the properties on the Load panel tab in the load properties dialog box.
The properties are:
Spanning Single: in the direction of the primary axis only
Double: along the primary and secondary axes
Primary axis direction If Spanning is set to Single, you can define the
primary axis direction by picking a part in the
model and setting this option to Parallel to part or
Perpendicular to part.
To manually define the primary axis weight when
Spanning is set to Double, you must also define
the primary axis direction.
Automatic primary
axis weight
Yes: Tekla Structures automatically calculates the
load portions for primary and secondary directions.
No: Enter the weight for the primary direction in
the Weight field. Tekla Structures calculates the
weight for the secondary direction by subtracting
this value from 1.

Loads
Example When using double spanning, automatic primary axis weight and the weight value affect the
proportions of the load which is applied to the primary axis and to the perpendicular axis.
• If Automatic primary axis weight is Yes, the proportions will be in proportion to the third
power of the span lengths in these two directions, i.e. the shorter the span, the bigger the
proportion of the load. The Weight value does not matter.
• If Automatic primary axis weight is No, the given Weight value (0.50 in this example) is
used to divide the load.
2.5 Working with loads
To modify the properties of a load, double-click it in the model to open the relevant load
properties dialog box.
When you have finished, click Modify to update the properties of the load in the model.
Topics Changing loaded length or area (p. 54)
Scaling loads in model views (p. 54)
Defining varying wind loads (p. 55)
Load dispersion angle The angle by which the load is projected onto the
surrounding elements.
Use continuous
structure load
distribution
Yes: for uniform loads on continuous slabs. For the
first and last spans, the distribution of support
reactions is 3/8 and 5/8, instead of 1/2 and 1/2.
No

Loads
Changing loaded length or area
As well as changing load properties, you can modify loads by:
• Moving line load ends
• Moving uniform load corners
• Changing the shape of openings in loads
• Adding corners to uniform loads
Handles Tekla Structures indicates the load reference points (the ends and corners of line, area, and
uniform loads) using handles. When you select a load, the handles are magenta.
You can use these handles to move load ends and corners:
1. Select the load to display its handles.
2. Click the handle you want to move. Tekla Structures highlights the handle.
3. Move the handle(s) like any other object. See Moving an object. If you have Drag and
drop on, just drag the handle to a new position. See Moving an object using drag-and-
drop.
To add corners to uniform loads, use the Modify Polygon Shape command. See Modifying
the shape of a polygon.
Scaling loads in model views
You can have Tekla Structures scale loads when you are modeling. This ensures that loads are
not too small to see, or so large that they hide the structure.
To scale loads in model views, click Tools > Options > Options... > Load modeling and go to
the Arrow length tab:

Loads
Example You define that point loads with magnitude of 1 kN or less are 250 mm high in the model, and
point loads with magnitude of 10 kN or more are 2500 mm high. Tekla Structures linearly
scales all point loads that have a magnitudes between 1 kN and 10 kN between 250 mm and
2500 mm.
Defining varying wind loads
The Create Wind Load (p. 63) command allows you to define which zones have concentrated
wind load. Each zone is the height of the wall. Define the width of the zone using either
dimensions or proportions. You can define up to five zones for each wall.
In the example below, the loads in the global x direction are multiplied by 3 at both corners of
wall 1.

Loads
The Wind load generator (28) dialog box contains one tab for each wind direction.
2.6 Load reference
This section consists of the reference pages for the load commands.
To create loads, use the icons on the Loads and Analysis toolbar or select a command from
the Analysis > Loads menu. The following table lists the commands for creating loads and
gives a short description of each one.
Load Groups...
Synopsis This command displays the Load Groups dialog box that you can use to manage load groups.
Command Icon Description
Load Groups... (p. 56) Displays the Load Groups dialog box.
Create Point Load (p.
58)
Creates a point load at a picked
position.
Create Line Load (p.
59)
Creates a line load between two picked
points.
Create Area Load (p.
60)
Creates an area load using three picked
points.
Create Uniform Load
(p. 61)
Creates a uniformly-distributed
polygonal area load using at least three
picked points.
Create Wind Load (p.
63)
Creates wind loads on a structure.
Create Temperature
Load (p. 62)
Defines a temperature change in a part,
or a temperature difference between
two part surfaces.

Loads
Description Tekla Structures lists all the existing load groups in the Load Groups dialog box. Use the
dialog box to view, define, modify, and delete load groups.
Usage Click Analysis > Loads > Load Groups....
To define a new load group:
1. Click Add.
2. Select the default load group from the list.
3. Click the load group name to modify it.
4. Click the load group type and select a type from the list box.
5. Click the load group direction to modify it.
6. To indicate compatibility with existing load groups:
• In the Compatible column, enter the number you have used for the load groups that
are compatible with this load group.
• In the Incompatible column, enter the number you have used for the load groups that
are incompatible with this load group.
7. Click OK to close the dialog box.
To modify an existing load group:
1. Select the load group from the list.
2. Change the name, direction, group type, or compatibility indicators.
3. Click OK to close the dialog box.
To delete a load group:
1. Select the load group from the list.
2. Click Delete.
3. Click OK in the warning dialog box. This also deletes the loads in the load group.
Column Description More information
Current The @ symbol identifies the
current load group. To change
the current load group, select a
load group and click the Set
current button.
Load group
properties (p. 43)
Name Unique name of the load group.
Type Load group type, based on the
action that causes the loads in
the group.
Direction Direction of the action that
causes the loads in the load
group.
Compatible A number that identifies all the
load groups that are compatible
with each other.
Load group
compatibility (p. 43)
Incompatible A number that identifies all the
load groups that are
incompatible with each other.
Color The color that Tekla Structures
uses to show the loads in the
group.
Load group
properties (p. 43)

Loads
To find out which loads belong to a load group:
1. Open the Load Groups dialog box.
2. Select a load group in the dialog box.
3. Click the Loads by load groups button. Tekla Structures highlights the loads in the
model.
To find out which load group a load belongs to:
1. Open the Load Groups dialog box.
2. Select a load in the model.
3. Click the Load groups by loads button. Tekla Structures highlights the load group in the
dialog box.
To move a load to a different load group:
1. Select the load in the model.
2. Select a load group in the Load Groups dialog box.
3. Click the Change load group button.
To export load groups:
1. Select the load groups to export in the Load Groups dialog box.
2. Right-click and select Export... from the pop-up menu.
3. In the Export Load Groups dialog box, browse for a folder and enter a name for the load
group file.
4. Click OK.
To import load groups:
1. In the Load Groups dialog box, right-click on the load group list and select Import... from
the pop-up menu.
2. In the Import Load Groups dialog box, browse for the load group files (.lgr) to import.
3. Click OK.
See also Working with load groups (p. 44)
Grouping loads (p. 42)
Create Point Load
Synopsis This command creates a point load at a position you pick.
Preconditions Shift the work plane to create loads perpendicular to sloped parts.
When you delete a load group, Tekla Structures also deletes all the loads
in the load group.
If you try to delete the only load group, Tekla Structures will warn you.
At least one load group must exist.
You can include several load groups in one load group file.

Loads
Description Tekla Structures creates the point load using the properties in the Point Load Properties dialog
box. The filename extension of a point load properties file is lm1.
Usage 1. Double-click the Create point load icon.
2. Enter or modify the load properties.
3. Click Apply or OK to save the properties.
4. If you have selected the Attach to member option, select the part to attach the load to.
5. Pick the position of the load.
See also Points
Creating a point
Using commands
Create Line Load
Synopsis This command creates a line load between two picked points.
Preconditions Shift the work plane to create loads perpendicular to sloped parts.
Description Tekla Structures creates the line load using the properties in the Line Load Properties dialog
box. The filename extension of a line load properties file is lm2.
Field Description More information
Load group
name
The load group to which the load
belongs.
Grouping loads (p.
42)
Load Groups... (p.
56)
Magnitude tab Load magnitudes in the x, y, and
z directions of the work plane.
Load magnitude (p.
49)
Load
attachment
Indicates if the load is attached
to a part.
Attaching loads to
parts or locations (p.
50)
Load-bearing
parts
Parts to which the load is
applied, or not applied, on the
basis of part names or selection
filters.
Applying loads to
parts (p. 50)
Bounding box
of the load
Dimensions of the bounding box
in the x, y, and z directions.
Load panel tab Properties used in the load panel
load distribution method.
Modifying load
distribution (p. 52)
Field Description More information
Load group
name
The load group to which the load
belongs.
Grouping loads (p.
42)
Load Groups... (p.
56)
Load form Defines how the load magnitude
varies along the loaded length.
Load forms (p. 48)

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