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UBC Theses and Dissertations

Repairing and retrofitting of non-seismically designed reinforced concrete circular bridge piers with low grade glass fibre reinforced polymer Hossain, Md. Mosharef

Abstract

Many of the highway bridges in Canada have passed their anticipated service life and do not meet the current seismic standard because of seismic design code upgradation. These bridges either need to be demolished or seismically upgraded causing a huge impact on the economy. A cost-effective alternative to current rehabilitation materials is required that can serve the purpose reliably. Glass Fibre Reinforced Polymer is a composite material that has emerged as a viable solution to this with its attractive mechanical properties, corrosion resistance and ease of application. This thesis presents an experimental investigation on the effect of repairing and retrofitting on the performance of damaged and deficient reinforced concrete circular bridge piers using a low grade GFRP. Market available bi-directional GFRP fabrics, commonly used for non-structural application like boat and yacht strengthening were used and their mechanical and bonding properties were obtained by laboratory test. The effect of this GFRP confinement thickness on the compressive strength of concrete was evaluated by testing cylinders confined with GFRP layers having a variable thickness. The effect was further investigated on the performance of 1/3 scale circular bridge piers by repairing and retrofitting with 2 layers and 150 mm overlap length of GFRP. Performance of these piers was compared in terms of lateral load capacity, drift, ductility and energy dissipation capacity with deficient pier. Finally, the performance of repaired and retrofitted piers under simulated seismic aftershocks was investigated and compared. Results of this study show that GFRP repaired pier can restore its strength with increased ductility and retrofitting it before damage improves the flexural capacity by 27%, energy dissipation capacity by 140% and ductility by 73%. Also, the retrofitted pier was capable of withstanding six consecutive seismic loading whereas the repaired pier failed after only two sets of seismic loading.

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Attribution-NonCommercial-NoDerivatives 4.0 International