Seismic Performance of FRP-Reinforced Concrete Columns

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The corrosion problem of steel reinforcing bars is the greatest factor in limiting the life expectancy of reinforced concrete (RC) structures. In some cases, the repair cost can be twice as high as the initial cost. One promising solution to the problems caused by deterioration of steel reinforcement is the use of the Fibre-Reinforced Polymer (FRP) reinforcing bars in concrete structures. FRP materials in general offer many advantages over conventional steel, such as light weight and corrosion-resistance. However, they have linear-elastic behaviour till failure, different bond characteristics, low strength under compression and shear stresses, and a relatively low modulus of elasticity compared to steel. These characteristics of FRP materials make the behaviour of FRP-RC structures different from their counterparts reinforced with steel and raise concerns regarding the ductility performance, shear capacity and integrity of FRP-RC structures, especially under seismic loads. Bridges and parking garages are prime examples of concrete infrastructure subjected to harsh environmental and loading conditions where the application of FRP reinforcement has high potential. Reinforced concrete columns are primary structural elements in such structures and the most critical members in case of a seismic (earthquake) event. However, design guidelines are lacking due to the very limited data available on the seismic effects on these columns. This research work is attempting to partially fill this gap. Experimental and analytical investigations on the structural performance and ultimate capacity of FRP-RC columns under seismic-simulated loading conditions will be carried out. The experimental work will be conducted on full-scale column specimens representing the most critical part of a column right above the foundation level. The analytical modelling, however, will be performed using nonlinear finite element analysis to model the complex distribution of stresses and strains in columns while considering the mechanical properties and bond characteristics of FRP bars. The results of this research work will be formulated into design equations and guidelines for deformable and integral columns. In addition, this proposed research program will contribute to the unique and highly specialized training of four graduate students (PhD & MSc) in the area of advanced composite materials for concrete structures fulfilling the increasing demand for HQP in Canada’s structural engineering community. By avoiding steel corrosion, better understanding the structural behaviour, and the development of design guidelines for such primary elements, this research will lead to new structures with improved performance, better durability and reduced life-cycle cost, which will benefit infrastructure owners such as Ministries of Transportation, Municipalities and Public Works.