Cracks of structural members caused by rebar corrosion directly influence the service life of reinforced concrete structures. Therefore, it is important to monitor early corrosion evolution of the rebar and take the early steps to overcome the situation. In this paper, the response relationship between wavelength variation of Fiber Bragg grating (FBG) sensor and mass loss rate of the rebar is derived. The accuracy of the proposed theoretical model is verified by the electricity accelerated rebar corrosion experiment. It indicates that the theoretical model matches well with the tested value. Moreover, in this study, real-time online early monitoring of rebar corrosion evolution is built.

Summary This research explores the seismic damage response of a frame–shear wall reinforced concrete structure exposed to progressive seismic excitations. The shear wall structure is a three‐storey one‐quarter‐scaled reinforced concrete structure. The test was conducted by applying progressive seismic excitations using a shaking table. The shear wall structure experienced inelastic deformations under high seismic excitations that eventually caused the transformation of the structure from a state of elastic deformation to a state of highly inelastic deformation. Damage in the form of plastic hinges occurred because of induced dynamic instability in the structure. The monitored seismic responses in this research includes the variation in the residual strains and their dynamic time histories. Precise and detailed measurements of varying strain responses and effective estimation of damage response within the structure have been a primary goal in this research. Successful implementation of fibre Bragg grating (FBG) strain sensor is presented and applied in this experiment because of its enhanced sensitivity towards monitoring the structural dynamic strain response. The presented research also evaluates the suitability of FBG strain sensors in dynamic testing of a frame–shear wall asymmetric structure by comparing the damage response obtained through FBG sensors and the predictions developed from the dynamic properties of the test structure, monitoring the progress in structural damage and predicting the cracks inside the structure. The monitored responses obtained through a series of tests prove that FBG sensors have the advantages of significant accuracy, small size, and good embedding abilities. It demonstrates its promising failure monitoring abilities and potentials for the crack detection. The results achieved through this research would be beneficial to validate existing numerical simulation and analytical procedures, particularly for the structures with inherent asymmetry. It has been demonstrated in this paper that (a) the structure entered into the critical state when the ground motion excitation was 0.5 g with invisible cracks, (b) a sudden change in the residual strain response can help in detecting the initiation of a crack, and (c) the damages in the structure were due to the formation of the plastic hinges at the flexible edge of the structure near the beam–column joints.

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