CONVENTIONAL MODELS FOR CREEP IN NORMAL AND HIGH-STRENGTH CONCRETE

Predicting creep in concrete structures is still highly uncertain, with current models for creep in cement concrete differing in their accuracy and complexity. As high strength concrete is of interest in the building industry the contemporary concrete models should cover higher grades of concrete. This required calibration of creep models for wider range of concrete strengths. The paper presents and compares the models for creep in cement concrete included in the ACI 209R-92 report, Eurocode 2 and fib Model Code 2010. For the presentation and comparison of the creep models, creep coefficients are used as the most common and understandable parameter in the analysis of time-dependent deformation of concrete. The main factors affecting the prediction of concrete creep are outlined, comparing the influence of concrete grade, environmental conditions, member size and loading conditions. Models currently used for creep in cement concrete are based on many years' theoretical and experimental research. They enable a more accurate analysis and better assessment of the time-dependent deformation of concrete structures at the design stage. Their complexity is significantly reduced and a range of influencing parameters are excluded from the models for simplicity and easy adaptation at the design stage.