This study introduces an innovative scheme of bridge superstructure for expedited construction, improved serviceability, and extended life span. The new bridge superstructure is assembled from precast prestressed decked bulb T-beams reinforced and prestressed with corrosion-free fiber-reinforced polymer (FRP) materials. An experimental investigation accompanied by analytical and numerical simulations was developed to evaluate the performance of the newly developed beams. Through the experimental investigation, three single decked bulb T-beams were constructed and tested to failure. The first beam, served as a control beam, and was prestressed and reinforced with conventional steel strands and reinforcing bars. The second and third beams were prestressed and reinforced with carbon-fiber cable composite (CFCC) strands and carbon-fiber-reinforced polymer (CFRP) tendons, respectively. The investigation revealed that the performance of beams reinforced with CFRP tendons or CFCC strands was comparable with the performance of the control beam at both service and ultimate limit states. All three beams exhibited high load-carrying capacity with large corresponding deflection and fair amount of absorbed energy before failure. The study showed that the corrosion-free FRP-reinforced decked bulb T-beams can be safely deployed in construction to enhance the performance and extend the life span of bridge superstructures.

Eleven decked bulb T beams were constructed, instrumented, and tested under shear loading to failure. Nine beams were reinforced and prestressed with carbon-fiber composite cable (CFCC) strands, whereas one beam was prestressed with conventional lowrelaxation steel strands and one beam was reinforced with non-prestressed CFCC strands. Half the span of each beam was reinforced with CFCC stirrups, whereas the other half was reinforced with conventional steel stirrups. Both ends of each beam were tested to evaluate the performance of CFCC stirrups versus that of steel stirrups. The investigation addressed the shear performance with respect to several shear parameters, including shear-span-to-depth ratio, stirrup spacing, prestressing force, and type of longitudinal and transverse reinforcement. All test beams failed by crushing of concrete in either the web or the top flange. No rupture of CFCC stirrups was experienced in any of the test beams. The performance of CFCC stirrups was analogous to that of steel stirrups with the exception that steel stirrups demonstrated a yield plateau before concrete failure. Beam ends with CFCC stirrups attained cracking and ultimate shear capacities similar to those attained in ends with steel stirrups. Results from the experimental investigation were compared with the theoretical values predicted using some available shear design guidelines for steel and CFCC reinforcement. In addition, modifications for current AASHTO LRFD shear design equations and its possible implementation in the ACI shear design guidelines are proposed based on the experimental results.

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Fiber-reinforced polymer (FRP) materials have been widely implemented in strengthening concrete structures. Their performance under fire events, however, has not been fully addressed. The lack of fire research imposes limitations on the use of FRP materials in structural applications, where fire is a concern. An experimental program was developed to investigate the performance of rectangular reinforced concrete beams flexurally strengthened with FRP materials under fire/loading events. Thirteen beams were constructed and tested to failure. Three beams served as control beams and were tested under three-point-loading setup at ambient temperature. Other beams were provided with supplemental fire insulation layers and were exposed to ASTM E119 fire scenario while being tested under the same loading setup. The experimental investigation revealed that the common hypothesis of ignoring the strength of the FRP system during fire is inaccurate and underestimates the performance of the strengthened structural element during fire events.