Classification

For each intermediary section, the classification is determined and the proper section check is performed. The classification can change for each intermediary point. For each load case/combination, the critical section classification over the member is used to perform the stability check.

So, the stability section classification can change for each load case/combination. However, for non-prismatic sections, the stability section classification is determined for each intermediary section.

The classification described in SIA263 is based on the calculation method. The calculation method in SIA263 distinguishes the method used respectively to determine the internal forces and to perform the section and the stability check.

A parallel can be made between the calculation method of SIA263 and the section classification proposed in EN 1993.

According to SIA263 Table 5a-5b ,  cross sections are classified in 4 types:

• PP (plastic-plastic) or class 1
• EP (elastic-plastic) or class 2
• EE (elastic-elastic) or class 3
• EER (elastic-elastic reduced) or class 4

The first letter of the classification denomination is related to the method used to calculate internal forces in the structure. The second letter indicates if we perform the section and the stability check with a elastic or a plastic approach. Finally, we must note that the steel code SIA263 is essentially oriented for symmetrical and bisymmetrical profile like I profiles. In the present modulus, other profiles are calculated by using a classic elastic approach (EE classification).