Electronic Thesis and Dissertation Repository

Degree

Master of Engineering Science

Program

Civil and Environmental Engineering

Supervisor

Dr. F.M. Bartlett

Abstract

The need for rapid construction or replacement of highway bridge decks can be addressed by precast concrete elements reinforced with Glass Fiber Reinforced Polymer (GFRP) bars with cast-in-place joints made using Ultra-High Performance Concrete (UHPC). This thesis investigates the bond between GFRP bars and UHPC and splice length optimization to obtain narrow joints and simplified bar geometries. Multiple linear regression analyses of existing bond data indicate that the bar’s Young’s Modulus and embedded length are the most significant parameters that influence the average bond strength of sand-coated GFRP bars in UHPC: increasing either decreases the average bond strength. Linear-elastic uncracked Finite Element analysis of pull-out specimens indicates that reinforcing bars with low Young’s Moduli have highly non-uniform bond distributions along their length and so exhibit high peak bond stresses and low average bond strengths. The higher average bond strengths observed for High Modulus (HM) GFRP bars compared to Low Modulus (LM) GFRP bars is likely because the HM GFRP bars have lower interlaminar shear strength. A methodology for GFRP reinforcement design that synthesizes provisions from the Flexural Design Method in the Canadian Highway Bridge Design Code including an additional new step to determine bar splice lengths in UHPC was developed. Splice lengths and bond resistance factors for HM GFRP bars in UHPC are determined by reliability analysis to resist either bar stresses due to the factored applied moments or the mean ultimate tensile strength of the bar. A significant reduction in splice length can be achieved if splices are designed to resist the bar stresses at factored applied moments. A new resistance factor of 0.5 for bond of GFRP bars in UHPC is also recommended.


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