Behavior of Circular Reinforced-Concrete Columns Confined with Carbon Fiber–Reinforced Polymers under Cyclic Flexure and Constant Axial Load

AbstractDeficient concrete-bridge columns can be effectively upgraded by bonding on the exterior surface fiber-reinforced polymer composite sheets with the fibers oriented in the columns’ circumferential direction, thus providing additional confinement. The efficiency of this rehabilitation method has been proven by the results of a number of cyclic loading tests performed on column specimens. The number of these tests, however, is much less than similar ones performed on reinforced-concrete columns without fiber-reinforced polymer confinement. This paper presents cyclic flexural test on reinforced-concrete columns confined with conventional circular hoops and carbon fiber–reinforced polymer and subjected to different axial-load levels. In addition to enriching the available database, the tests in this research program were programmed such that failure would occur in the composite sheets to validate an innovative stress-strain model that considers the passive confinement provided by both transverse-steel ...