Sustainability of Transportation Structures Using Composite Materials to Support Trade and Growth
Shobeir Pirayeh Gar, Stefan Hurlebaus, John B. Mander, Wesley Cummings, Michelle J. Prouty, and Monique H. Head, June, 2014
Corrosion-induced deterioration of steel rebar is one of the main reasons for repair and rehabilitation programs for conventional steel-reinforced concrete bridge decks. According to the National Association of Corrosion Engineers (NACE), of all bridges in the United States, over 50 percent are constructed of conventional steel-reinforced or prestressed concrete, and one in three bridges is considered structurally deficient or functionally obsolete due to corrosion of steel reinforcement. NACE has estimated the annual cost of corrosion-related maintenance of highway bridges in the United States at $8.3 billion.
To overcome corrosion-induced structural issues, researchers have introduced and applied fiber-reinforced polymer (FRP) bars, over the past couple of decades, as a corrosion-resistant candidate for either conventional reinforcing steel or prestressing strands. High strength-to-weight ratio, corrosion resistance, and accelerated construction due to ease of placement of the bars and implementation are the special characteristics that make these bars an appealing alternative for either steel-reinforcing bars or prestressing strands.
This report presents the experimental and analytical investigations of structural performance of a full-scale American Association of State Highway and Transportation Officials (AASHTO) I-girder Type I, reinforced and prestressed with aramid-fiber-reinforced polymer (AFRP) bars, where the bridge girder is composite with a topping deck. The major objectives of this research included evaluating (1) the constructability, (2) the load and deformation capacities under either flexure or shear tests, and (3) the structural performance per AASHTO load and resistance factor design (LRFD) criteria.
The results of this research confirm the adequate strength and deformation capacities of the composite girder, satisfying the AASHTO LRFD criteria. The flexural capacity of the composite girder was about 1582 kNm (1167 kft.), which is 20 percent greater than the maximum factored load, 1326 kNm (978 kft.), per AASHTO LRFD. Under the flexure test, the failure mode of the girder was recognized as the tendon rupture in the bottom flange, where the maximum compressive strain in the topping deck did not reach a failure value equal to −0.003. Such a failure mode was expected because it is not practical to fit too many FRP bars within the bottom flange of the girder to over-reinforce the section and change the failure mode from tendon rupture to concrete crushing in the top fiber of the section.
Keywords: Bridge Girder, Aramid-Fiber-Reinforced Polymer (AFRP), I-Girder, Composite Action, Composite Material
ENTIRE REPORT (Adobe Acrobat File – 3.1 MB)