Analysis and Comparison of Experimental Tests of Barrier-Deck Slab Overhang Structures Using Steel and GFRP Reinforcement
Creators: Torres Acosta, Juan A.
Publisher: name: University of Alberta Library
Year: 2024

<p>Glass Fibre Reinforced Polymers (GFRP) have been commonly used as external or internal reinforcement of repaired or sound structures for some time in North America. GFRP-reinforced concrete (RC) technology has been implemented in bridge components like decks and barriers whose exposure to harsh environmental conditions is constant, given its non-corrosive nature. Despite their frequent use, some transportation ministries and contractors still see this technology as experimental and related to gaps in code provisions for repairs. For bridge barriers repairs, little to no provisions are offer in current codes; moreover, few studies conducted on bridge barriers using GFRPs have limited scopes, leaving out some critical aspects to assess bridge barrier-deck overhangs. This study was divided into an experimental and analytical phase. Experimental work included the fabrication of four concrete barrier-deck overhangs. Two served as controls by mimicking as-built structures using steel and GFRP reinforcement, while remaining ones simulated a repaired barrier-deck connection through bars doweled into deck. One of these specimens was fully reinforced with GFRPs and the other one was a hybrid structure (steel and GFRP bars). Structures were composed of a 1500×2500×250 mm deck and a single-sloped Alberta Transportation TL-4 bridge barrier connected at the tip of a 1500 mm-long overhang. Monostatic lateral load was applied until failure. Data gathered was used to analyze and compare response of specimens. RILEM beam-bond tests were also conducted to calibrate bond-slip models of GFRP bars embedded into concrete and bars with a surrounding epoxy resin embedded into concrete. For barrier-deck overhangs, one-way action weakened the barrier-deck joint which was able to be simulated using strut-and-tie models. By using this methodology, test-to-predicted ratios attained ranged between 1.15 to 0.99, showing good agreement to predict peak load. All specimens, regardless of reinforcement material or if doweled showed the same failure mechanisms. Furthermore, structures&#39; response was governed by the stiffness of reinforcement materials used in each specimen with steel-reinforced one showing the strongest and stiffest response of all and those reinforced with GFRPs showing the weakest; interestingly, hybrid structure did not achieve an intermediate response as expected but reported an early failure which was attributed by large tensile strains in the joint and poor confinement of this region. This latter aspect seemed to have contributed to low peak loads attained in all structures, except in steel-RC’s. In a second phase, an analytical model was developed to analyze same structures as tested ones under same monotonic setup. Program was able to predict with good accuracy peak load and failure mode as real structures with test-to-predicted ratios lingering unity; deflection calculations, however, underestimated real specimens’ response. This was attributed to model assumptions and limitations that limited its precision. Regarding RILEM beam-bond tests, bond-slip curves showed that the bond strength of a bar surrounded by epoxy resin will be 7.4% less to that of a bar in direct contact with concrete. Furthermore, both curves exhibit same trends with no other relevant aspects to highlight.</p>