Effects of pre-damage and cyclic compression on axial behavior of FRP jacketed concrete

Although large number of experimental data is available for the compressive behaviour of fibre reinforced polymer (FRP) confined concrete under monotonic increasing axial loading, experimental data is rare for the case of cyclic compressive stresses. In this study, concrete cylinders tested by the authors before under cyclic and monotonic compression stresses are evaluated with particular emphasis on cyclic loading and effect of existing pre-damage on the behaviour. The FRP jacketed specimens were either pre-damaged by testing before jacketing or undamaged. The test results are evaluated mainly in terms of longitudinal and transverse stressstrain relationships, as well as damage patterns, plastic strains and energy dissipation during the loading cycles. In the analytical part, two existing models were used to predict the axial strengths and corresponding axial strains of the specimens. One of the main conclusions of the study was that the envelopes of cyclic axial stressaxial strain relationships were almost identical with the monotonic axial stress-strain relationships of equivalent specimens tested under monotonic compression, with significant degradation of stiffness due to increasing plastic damage formed with increasing deformations.