Axial-bending interaction of high deformability FRP-confined circular concrete members

This paper examines the strength interaction and deformation capacity of structural membersincorporating high deformability concrete materials in which mineral aggregates are replaced by rubberparticles and provided with and without external FRP confinement. An experimental study on circularreinforced rubberised concrete members subjected to axial compression, eccentric compression andthree-point bending is presented. After describing the experimental arrangement and specimen details,the results and observations obtained from tests are provided and discussed. The test results enablethe direct evaluation of the strength interaction and deformation capacity of the specimens, and theinfluence of FRP confinement and rubber content to the performance of the investigated configurations.The results indicate that confined structural elements provided with high amount of rubber contentbenefit from the presence of rubber developing significantly larger deformation capacity whilstmaintaining relatively similar strengths, in comparison to unconfined members and members with lowerrubber content. A set of design-oriented expressions for constitutive modelling of FRP confinedrubberised and conventional concrete materials combined with variable confinement procedure foreccentric loading, are employed for assessing the strength interaction of circular sections investigatedin this paper. These procedures capture in a realistic manner the influence of rubber content on thestrength and deformation characteristics of confined members.