1st Croatian Conference on Earthquake Engineering 1CroCEE 2021

Fiber Reinforced Polymers (FRP’s) are widely used as composite materials in Civil Engineering applications in order to rehabilitate or strengthen existing structural elements. FRP’s have been used as flexural and shear reinforcement and also as a confining material mostly for concrete columns. Several studies have identified a large increase in terms of strength and axial deformation for confined concrete specimens. This paper presents a comprehensive review and evaluation of analytical models developed to predict the maximum longitudinal deformation of confined circular concrete columns subjected to compression. The equations of the models are applied on an extensive experimental database regarding test results of 847 FRP-confined cylindrical concrete columns under uniaxial compression. The database contains sections of concrete of different strengths confined with different types of FRP’s. The performance of each strain model is assessed through various statistical indicators, such as Root Mean Square Error (RMSE) and the Nash–Sutcliffe model efficiency coefficient (NSE). These statistical indexes compare the concordance between experimental maximum recorded strains and analytical predictions of ultimate strain. The most efficient models are identified, leading to important observations regarding the influence of main parameters on the behavior of FRP-confined concrete, such as the concrete and fiber material properties.