This calculator computes section capacities and utilisation factors of IPE and HE steel sections. It considers axial compression or tension, bending, and shear effects on the section.
According to EC3 Chapter 5.5, sections are classified as Class 1 to 4 depending on how their cross-section behave under compressive load.
Class 1 (Plastic): can form a plastic hinge with the rotation capacity required from plastic analysis without reduction of the resistance.
Class 2 (Compact): can develop their plastic moment resistance, but have limited rotation capacity because of local buckling.
Class 3 (Semi-compact): the stress in the extreme compression fibre of the steel member assuming an elastic distribution of stresses can reach the yield strength, but local buckling is liable to prevent development of the plastic moment resistance.
Class 4 (Slender): local buckling will occur before the attainment of yield stress in one or more parts of the cross-section.
The classification of a section depends on the width to thickness ratio of the parts subject to compression. Detailed table for classification can be found in Table 5.2.
Stress distribution of a section depending on Class 1 to 4
Tension
Tension capacity of a section is calculated as per EC3 Chapter 6.2.3 - Equation 6.6.