Destructive testing of a highway bridge strengthened with FRP systems

This dissertation presents in two parts the results of a research program aimed at evaluating the short-term flexural behavior of reinforced concrete (RC) decks and piers of a highway bridge strengthened with externally bonded fiber reinforced polymer (FRP) reinforcement. The objective of the research program was to provide full-scale test data to verify the theoretical design methodology based on a scientifically valid foundation.; Part I of this document focuses on the strengthening and testing to failure of the bridge decks. One of the three simply supported decks was strengthened using near-surface mounted (NSM) carbon FRP (CFRP) rods while another deck was strengthened using externally bonded CFRP strips. The three decks were tested to failure using four, 100-ton, hydraulic jacks by applying quasi-static load cycles. Test results indicated that the actual capacity of the bridge decks were higher than anticipated due to higher actual material strengths. After adjusting for the true material strengths, the experimental flexural capacities still exceeded the predicted values. This led to the conclusion that the addition of FRP reinforcement improved the flexural capacity of the decks and that the design strengths were achieved in the field. Additional differences between predicted and experimental results were related to the existence of some continuity at the supports.; Part II of this document presents the strengthening and testing to failure of the bridge columns. This part of the research program aimed at investigating the feasibility and effectiveness of using NSM CFRP rods to improve the flexural capacity of the columns. Flexural strengthening of two columns was achieved using NSM CFRP rods embedded on two opposite sides of the concrete columns and anchored to the footing using epoxy. The columns were wrapped with carbon composite sheets to provide lateral support to the mounted rods and to meet some seismic detailing requirements. Thickness of the jacket was determined using a formula that was developed for this purpose. The columns were tested to failure by applying static lateral loads in cycles. Test results indicate that the proposed strengthening technique is feasible and effective for improving the flexural capacity of RC columns. However, when upgrading bridge columns for flexure, full investigation of the upgraded structure should be made considering the new loads to ensure that the deficiency is not shifted to other structural members.