The material laws in EC2 vary between structural analysis and cross‑section design, incorporating different levels of physical complexity in the behaviour of concrete and steel depending on the objectives pursued.

This article details the different behaviour laws for concrete and steel, their distinct uses (structural analysis vs cross‑section design), and their limitations.

It explores how phenomena such as plastification, cracking, or even the tensile resistance of concrete are taken into account, and clarifies the safety factors and the possibilities for linearisation or other simplifications authorised by EC2 depending on the design step.

This topic is the second part of a series devoted to the flexural behaviour of reinforced concrete beams (2/4).