PERFORMANCE OF FRP-RETROFITTED CONCRETE BRIDGE COLUMNS UNDER BLAST LOADING

Contrary to military or essential government buildings, most bridges are designed without any con-sideration for blast resistance. Fiber-reinforced polymers (FRPs) can provide an effective means for strengthening of critical bridges against such loading. This study has focused on the effectiveness of FRP retrofi tting in the dynamic response of reinforced concrete bridge columns under blast loading. Using a simplifi ed equivalent I-section with a virtual material lumped at the two fl anges; a lightly meshed uniaxial fi nite element model was developed and successfully validated against previous stud-ies. The proposed model was then used for a thorough parametric study on the blast resistance of bridge substructures in the form of a single-column, two-column pier frame, and an entire bridge. The study showed the benefi ts of strengthening with composites against blast loading. The FRP tensile strength and diameter-to-thickness ratio, steel reinforcement ratio, and column length and damping ratio signifi-cantly affect the blast resistance of an FRP-retrofi tted bridge. Finally, based on the parametric study results, predictive equations with multiple linear regression and high order terms were developed sta-tistically for the FRP retrofi t design of single columns against blast loading