Image analysis method used in the seismic rehabilitation of squat reinforced concrete shear walls using CFRP sheets

This study investigates the effectiveness of using externally bonded Carbon Fiber- Reinforced Polymer (CFRP) sheets to restore the performance of earthquake damaged squat Reinforced Concrete (RC) shear walls. The test specimens have several detailing deficiencies associated with construction practices during the 1960s and 1970s. The specimens are first tested under cyclic load to simulate damage to the wall during an earthquake. The specimens are repaired using externally bonded CFRP sheets and tested again to evaluate the ability of the CFRP rehabilitation strategy to prevent premature shear failure and enhance the seismic performance of the wall specimens. To assist in understanding the behavior of the specimens, an image analysis method that is capable of capturing crack distributions, strain, and displacement fields in large-scale structural experiments is employed. The ability of the image analysis technique to detect debonding between the CFRP sheets and concrete is also discussed. Results of the study show that the use of CFRP sheets is capable of restoring the in-plane strength to a damaged RC shear wall. The image analysis technique is shown to be an effective tool in capturing crack distributions before they can be detected by an un-aided visual inspection while also being able to capture twodimensional displacement and strain fields.