1st Croatian Conference on Earthquake Engineering 1CroCEE 2021

Due to the necessity to strengthen existing reinforced concrete structures, innovative materials such as Fiber Reinforced Polymers (FRP’s) may be used to comply with increasing loads and modern regulations. Externally bonded FRP overlays have been used to increase the flexural, shear and compressive capacity of concrete. The use of externally bonded FRP’s to confine circular concrete structural elements has shown experimentally a significant increase of the compressive concrete strength. In the course of the development of composite materials since the 1990s, along with the methodologies concerning their application, a plethora of models have also emerged in order to determine the FRP-confined compressive concrete stress with good accuracy. This paper presents a study on the compressive strength of concrete confined with externally bonded fiber reinforced composite materials. In order to evaluate the experimental data and analytical models an extensive database of experimental data is created from experiments reported in the literature, sharing common test features (conventional concrete cylindrical specimens confined using FRP composites of various fibers aligned perpendicular to the longitudinal axis of the cylinder). Based on the collected experimental data a statistical analysis is performed in order to identify the major parameters that affect the ultimate confined axial stress. Furthermore, the experimental data are used in a series of available models in order to determine the analytical predictions of ultimate stresses in comparison to the experimental ones. Statistical methods are used to quantify the analytical models’ efficiency and to identify major factors that affect the models’ performance.