Numerical simulation of concrete creep behaviour using integral creep algorithm with alternating stresses

To investigate the accuracy of commonly used algorithms for prediction of creep and shrinkage effects in concrete structures, a comparative study is carried out using the finite element (FE) models with various user-defined time-dependent material properties. Numerical results are compared with available benchmark tests to justify the FE models. Results show that the FE model following the concrete integral creep (CIC) algorithm is close to the test result. The secondarily developed subroutine on the universal commercial FE platform is able to represent the time-dependent behavior of the concrete cylinders. CIC shows higher accuracy once alternating load history is considered, though the rate of creep method (RCM) and age-adjusted effective modulus method (AEMM) show the same accuracy as CIC under constant load. CIC shows outstanding compatibility with the material model specified in contemporary design codes. It seems that the CIC model can be used for a detailed evaluation of concrete structures, while RCM and AEMM might be used for preliminary and rough analysis.