Stiffness analysis of a steel connection (EN)

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This tutorial shows how to use IDEA StatiCa Connection to model, design and check a structural steel joint and calculate the stiffness of the connection.

1 New project

Launch IDEA StatiCa (download the newest version) and select the Connection application.

Create a new project by selecting the starting template closest to the desired design. Fill in the name, select Eurocode as the design code, and the steel grade as S235.

2 Geometry

Three members were automatically created.

3 Load effects

One load effect was automatically generated. Change the values of internal forces in the chart.

4 Design

Now define a set of manufacturing operations to model the complete connection. Start with the mouse right-click at the Operations in the tree in the 3D scene. Add a New operation.

In dialog with all available manufacturing operations, choose the End plate operation.

Select the desired bolt grade and size (M20 10.9).

Define the right properties of the created end plate.

Copy operation EP1: mouse right-click at the EP1 and select Copy.

Change the member related to EP2.

Add the Stiffener operation to the design.

Modify the STIFF1 operation.

The design is complete.

5 Stress/strain analysis

To have a complete picture of the connection behavior, the stress/strain analysis is run first.

Select Calculate in the ribbon to run the analysis based on the CBFEM method. The numerical model is automatically generated, the calculation is performed, and you can directly see the overall check results in the top-left corner of the scene.

More detailed results can be displayed in the Check tab: activate the Strain check, Bolt forces, Mesh and Deformed shape of the connection in the ribbon to get a full picture of what is happening in the joint. 

 6 Stiffness analysis

To keep the stress/strain results, copy this project item. 

In the copied project item, change the analysis type to Stiffness (ST) in the top ribbon.

Verify that beam B1 is set as an Analysed member, as shown below. (If you want to switch Analysed member, you can use the right mouse button and set another member as an Analysed member).

The “Theoretical length for My, Mz” can be set for the analyzed member. For more information about the theoretical length, please see Theoretical background and Video – tips for stiffness analysis.

Start the stiffness analysis by clicking on the Calculate button in the top ribbon. 

The result of the analysis and the load path can be checked in detail in the Rotational stiffness tab. For a better understanding of the results, see the Theoretical Background.

7 Modification of connection

To keep the project Stiffness analysis1, copy it and create Stiffness analysis2.

Modify endplate EP1 to increase the rigidity of the connection Stiffness analysis2.

Run the stiffness analysis again. You can notice the change in the classification of the connection rigidity from Semi-rigid to Rigid.

For more information on stiffness analysis, please check out our Theoretical background and video.

8 Report

At last, you can review the Report. IDEA StatiCa offers a fully customizable report to print out or save in an editable format.

You have performed a stiffness analysis of a structural steel joint according to Eurocode (EN).

9 More information

Video – introduction to stiffness

Video – tips for stiffness analysis

For more information, please visit our Theoretical background.

Sample files


Tips for stiffness analysis

Correct inputs for joint stiffness analysis

How to make stiffness analysis for complex joints efficiently

Connection Wednesdays - Game-changing joint stiffness analysis