Flexural behaviour of indeterminate concrete beams reinforced with FRP bars

This paper presents a theoretical study of the flexural behaviour of indeterminate concrete beams reinforced with fibre reinforced polymer (FRP) bars using a local deformation model developed by the authors. The model is firstly presented and its performance compared with tests on simply supported and continuous concrete beams reinforced with FRP bars. A detailed theoretical investigation is then conducted by applying the model to continuous beams reinforced with FRP bars in order to predict the bending moment distribution, as well as the progressive formation of flexural cracks and associated crack spacings and crack widths. Of particular interest is the ability of the model to determine the deformations in highly stressed regions in the beam. Based on the theoretical results, comments are made as to the ductility and overload behaviour of concrete beams reinforced with FRP bars in comparison to concrete beams reinforced with steel bars. All results and associated comments are dependent on certain assumptions and are dependent on the input parameters used in the model. The results are found to be particularly dependent on the bond characteristics between the FRP bar and surrounding concrete.