Tips for stiffness analysis

In every structure, the redistribution of the internal forces will occur and will change the behavior of the structure. The stiffness of the joint is crucial and needs to be determined. Use stiffness analysis to determine, if the joints are pinned, semirigid, or rigid.

We will provide some tips about stiffness analysis.  In this video will be clarified terms such as:

• theoretical member length
• stiffness classification
• how the rotation dependency on the bending moment determines the secant and initial stiffness

Besides, we will also explore the classification limits for rigid and semi-rigid class. And we will show you some theoretical background valid for stiffness analysis. 

Performing of the stiffness analysis on dozens of load effects is not effective and correct. The best way is to prepare the load effects in a special way and avoid wasted time and disorder in the results. Three load effects will be prepared for stiffness analysis. Bending moment, bending moment and shear force interaction and all 6 internal forces. That is the correct load effect definition for stiffness analysis.

According to the EN 1993-1-8 cl. 5.2.2.5 the theoretical member length has to be set for the right classification. What does it mean anyway and how I can define it in IDEA StatiCa Connection.

Braced frames have a different limit for the stiffness classification according to the EN 1993-1-8 cl. 5.2.2.5. How to set this parameter correctly in the IDEA StatiCa Connection?