Experimental study of seismic behavior of partially corrosion-damaged reinforced concrete columns strengthened with FRP composites with large deformability

Fiber reinforced polymer (FRP) jackets with a large rupture strain are formed by embedding polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) fibers in the epoxy resin binder. PEN and PET fibers are made of recycled materials (e.g., PET bottles), possessing the advantages of large rupture strain, low elastic modulus, environmental protection and economy. To simulate the actual non-uniform corrosion of steel bars in the columns, the corrosion rate of steel bars in the plastic hinge region was designed as 15% by using electrochemical corrosion method. Partially corroded reinforced concrete columns with different reinforcement ratios were strengthened with carbon FRP (CFRP) and PET-600 composites respectively. All the columns were subjected to the quasi-static tests. The seismic performance of hysteretic hoops, failure modes, residual displacement, stiffness degradation, damping ratio and energy dissipation were analyzed. The experimental results showed that PET-600 and CFPP strengthened columns had the basically same anti-seismic performance, indicating that PET-600 could be worked as a new type of high performance strengthening materials in the structure strengthening field.