A unified model that predicts the non-linear flexural response of corroded RC beams repaired with fibre reinforced polymer (FRP) sheets was developed. The model accounts for the effects of corrosion and FRP-wrapping on the transfer of load from the steel to the concrete between flexural cracks. The effects of the additional FRP reinforcement and the reduction in the steel area due to corrosion on the beam strength are predicted by the model. The beam cross section is discretized into finite layers while the beam span is modelled as a series of elements based on the mean crack spacing. The model was implemented into a new computer program. A comparison of the model’s predictions with experimental results showed that the model accurately predicted response of both corroded and FRP – repaired beams. (Fig. 6).
Mid-span deflection (mm)
Figure 6. Analytical model and results
In Fall 2005, the ISIS Waterloo group in collaboration with the C3 group successfully implemented the FRP repair onto a bridge girder in the region of Waterloo along with sensors to monitor the performance of the repair system. The FRP repair will be monitored over time to assess its effectiveness in the field. Figure 7 shows a photo of the FRP sheets on the girder.
Figure 7. Photo of CFRP repair on the bridge girder
FRP composites are viable for the strengthening or repair of reinforced concrete beams that are experiencing steel reinforcement corrosion capable to maintain the structural integrity, serviceability and ultimate monotonic strength. The results in this paper provided important benchmark data, analytical modeling as well as field implementation of the FRP repair.
The author is a project leader in the Intelligent Sensing for Innovative Structures Network and wishes to acknowledge the support of the Network of Centres of Excellence Program and Natural Sciences and Engineering Research Council of Canada.
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