Experimental Investigation of the Lateral Load–Carrying Capacity of a Developed GFRP-Reinforced TL-5 Bridge Barrier Using Special Profile Hooked Bars

Abstract

Old concrete bridge barriers suffer from corrosion-induced degradation due to the effects of freeze–thaw cycles and the application of winter deicing salt. To replace such deteriorated bridge barriers while aiming to reduce maintenance costs and improve their life expectancy, rust-free high-modulus (HM) glass fiber–reinforced polymer (GFRP) bars with 180° hooks are utilized as primary reinforcement in the barrier wall. A proposed TL-5 bridge barrier developed in this research incorporated 15M and 13M GFRP bars as vertical (transverse) reinforcement in the barrier front and back faces at a 300-mm spacing, respectively, and 15M GFRP bars as horizontal (longitudinal) reinforcement in the barrier wall. The connection between the deck slab and the barrier wall utilized GFRP bars with 180° hooks for proper anchorage. To study the structural behavior, the crack pattern and the ultimate load–carrying capacity of the proposed barrier wall under an equivalent transverse vehicle collision force, a 40-m-long GFRP-reinforced TL-5 barrier was constructed and statically tested to failure under transverse line load at interior and end locations. While trapezoidal flexural cracks were developed at the traffic side of the barrier wall during loading, punching shear crack occurred at the loading location, leading to barrier failure. The experimental ultimate load–carrying capacities of the barriers were observed to be far greater than the load capacity required by current design codes. GFRP bar strain and concrete strain readings at the barrier deck showed very low strains at failure compared to the material’s nominal failure strain. To study the pullout capacity of the GFRP bars with 180° hooks reinforcing the lower tapered portion of the barrier wall and embedment into the deck slab, a representative concrete slab with various embedded GFRP bars was constructed. Pullout tests on GFRP bars with straight ends, hooked ends, and hooked ends with unbonded straight portions of the bar were performed. The results showed that the average pullout capacities of the tested bars are far greater than the pullout capacity of 100 kN specified in current standards for TL-5 HM-GFRP concrete barriers. The GFRP bar’s experimental pullout capacity can be used to determine the resisting moment at the barrier deck connection for compliance with the code-specified factored applied moment at this location.