The applicability of the stress–strain formulations in Eurocode 2 (BS EN 1992-1-1:2004 and British Standard (BS 8110-2:1985)) for modeling the compressive behavior of concrete in non-linear structural analysis is investigated. Both codes employ similar expressions governed by a key parameter–k-factor. The current formulation incorporates an empirically calibrated constant to align the theoretical tangent modulus with the secant modulus obtained from experimental data. However, this constant remains fixed and does not account for variations in concrete properties, resulting in mathematical inconsistency within certain strength ranges. A modified equation for determining the k-factor is derived to overcome this limitation. Comparative and validation analyses demonstrate that the proposed formulation provides a more reliable prediction of the stress–strain response, particularly for low- and normal-strength concrete.
Hameed Shakir Al-Aasm (Wed,) studied this question.