Comparison of Section Classification Procedure of Different Codes

The cross-section classification is essential to identify local buckling in steel sections. Local buckling restricts the section from attaining its maximum moment capacity. Cross section classification is based on the behavior of the element under direct and bending compressive stresses. Limit on width to thickness ratio of elements in a cross section is the governing criterion for the section classification in different national codes. In the case of seismic design, the post yield ductility is an important parameter; therefore, it is particularly essential to prevent local buckling. Design codes of different countries provide different limiting values for the section classification. The present study discusses the approach of various national codes towards cross section classification. The approach of Eurocode 3, AISC 341, AISC 360, BS 5950 and IS 800 on issues like section classification of members subjected to axial and flexural compression, sections with elements of different classes are explained and their salient features are compared with each other. It is observed from the study that, amongst the codes considered, AISC provides the most stringent limits for seismically compact section, whereas, for other class of sections Eurocode 3 limits are more stringent.