Evaluation of Repair Technique Effectiveness for Bridge Barrier/Deck Systems with Glass Fiber Reinforced Polymer Bars Using Mechanics-Based Modeling

Degradation of traditional steel reinforcement in concrete used in bridge decks and barriers due to aggressive environments and use of de-icing salts in Canada has prompted a shift to using non-corrosive reinforcement materials in these applications. Non-corrosive reinforcement includes options such as stainless steel or glass fiber reinforced polymer (GFRP) bars. GFRP reinforced concrete bridge decks and barriers have become relatively popular in parts of eastern Canada but there are concerns in other regions about how these structures may be repaired if damaged by events such as vehicle impact. In this study the response of bridge deck-barrier systems reinforced with GFRP, steel reinforcement, and combinations of the two is investigated using an analytical approach. Barriers considered are single-slope TL-4 barriers commonly used for provincial highways in Alberta. Modeling is based on moment–curvature relationships, curvature integration to assess flexural deformation, bond-slip deformation/failure mechanisms, and shear failure mechanisms. As-built barriers constructed with steel or GFRP bars are considered and compared to repaired systems, consisting in saw-cut and doweled bars to create post-installed anchorage systems. Various anchorage bond-slip approaches are considered. The model is validated against previously tested concrete beams and tests on bridge barriers reinforced with steel or GFRP bars. A parametric study investigates the effects of bar material type (steel/GFRP), spacing, overhang length, and anchorage depth on the response of barrier-deck systems. Results show that though barrier capacity is reduced with the retrofitted processes, repaired barriers are still able to resist the expected factored design load for a TL-4 barrier per the Canadian Highway Bridge Design Code (CSA S6:19). Further validation and refining of this model, particularly bond-slip responses, is planned via an experimental program currently underway.