Portland State University. Department of Civil and Environmental Engineering
Date of Award
Master of Science (M.S.) in Civil & Environmental Engineering
Civil and Environmental Engineering
Fiber-reinforced concrete -- Testing, Concrete beams -- Testing, Shear (Mechanics), Metal fibers, Polypropylene fibers
Severe premature deterioration has been reported in a large number of reinforced concrete (RC) structures in corrosive environments. This research project focused on the behavior of beams that contained corroded steel and were retrofitted with CFRP. The steel in RC beams were assumed to be fully corroded, representing the most severe loss in steel cross-section. Unidirectional CFRP sheets were used to strengthen the deteriorated beams. The experimental program included testing five simply supported rectangular cross section concrete beams. All beams were approximately 1/3rd scale models, 4in. x 6in. cross sections, and 6ft. long. In three beams, the oiled steel rebars for flexure and shear were safely pulled out of the formwork after the concrete had cured a few hours, leaving voids. This technique was used to represent the total loss in steel cross-section in an extremely corrosive environment.
The first specimen was a control beam with voids representing deteriorated steel. The second specimen was a plain concrete beam without voids. The third beam was another control specimen with flexural and shear reinforcement intact, representing the “original” beam before steel corrosion. The two remaining deteriorated beams were strengthened by externally bonding one and two layers of CFRP in the longitudinal and transverse directions. Beams were tested under third-point loading.
Load carrying capacity, deflection, and ductility of the beams were measured. Test results showed that one layer of CFRP increased the load capacity to slightly higher than the “original” control beam, and two layers of CFRP increased it by a factor of two. The retrofitted specimens had a higher stiffness under service load conditions. The predict contribution of CFRP to flexure and shear capacities based on ACI 440.2R guidelines were in good agreement with test results.
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Lingga, Needa M., "Behavior of Concrete Beams with Corroded Reinforcement Retrofitted with Carbon Fiber Reinforced Polymer" (2016). Civil and Environmental Engineering Master's Project Reports. 29.