Development of innovative designs of bridge barrier system incorporating reinforcing steel or GFRP bars
thesisposted on 08.06.2021, 12:49 by Hamidreza Khederzadeh
In harsh environment, corrosion of steel reinforcement causes durability problems. Glass Fiber Reinforced Polymer (GFRP) has emerged as an alternative to corrosion-related problem of steel bars in development of sustainable bridge deck and barrier walls. The current research program has been divided into five phases. In phase I, an extensive study has been conducted on pullout strength and bond behavior of pre-installed GFRP bars into concrete slabs and concrete cubes. In phase II, based on the Canadian Highway Bridge Design Code (CHBDC) factored applied moment at deck-wall junction, three configurations of GFRP-reinforced barrier detailing, using High-Modulus (HM) and Standard-Modulus (SM) GRFP bars, were proposed. The proposed barriers were tested by constructing five actual-size, 1.0-m long, PL-3 barrier models to determine their ultimate load carrying capacities and failure modes. In phase III, a full-scale PL-3 barrier made of GFRP-HM bars, with headed-end anchors as connecting bars to the deck slab, was constructed and tested under transverse static loading at both interior and exterior locations to-collapse to determine its crack pattern, failure mode and static ultimate load carrying capacity. In phase IV, from the trapezoidal failure pattern observed during testing the GFRP-reinforced PL-3 barriers, the research program was extended to revisit the triangular yield-line failure patterns in steel-reinforced PL-2 and PL-3 barriers specified in AASHTO-LRFD specifications. Experimental static tests to-collapse were conducted on constructed actual-size PL-2 and PL-3 steel-reinforced barriers, leading to more accurate expressions for their transverse load capacities developed based on the yield-line theory. In phase V, non-linear finite element analysis was conducted on GFRP-reinforced bridge barriers tested in phase III. The finite-element modeling was conducted to solely simulate the experimental test results for future research. A good agreement between experimental observations and numerical finite-element modeling was observed. Finally, this research led to (i) a more accurate design procedure for the GFRP - and steel-reinforced barrier wall and the barrier-deck joint, and (ii) design tables for the applied moment and tensile forces to be used to design the deck slab and the barrier deck-junction to resist transverse loading resulting from vehicle impact.