Evaluation of the effects of various environmental conditions on reinforced concrete columns wrapped with FRP sheets.

摘要

Although the short-term performance of reinforced concrete (RC) columns wrapped with fiber reinforced polymer (FRP) composite materials has been widely studied, research studies on the long-term performance are limited. The objective of this study was to evaluate the effects of various environmental conditions on the long-term behavior of RC columns wrapped with FRP sheets.; The experimental program comprised two parts; ambient environmental effect tests and corrosion tests. The environmental conditions considered in the ambient environmental tests included (1) freeze-thaw cycles, (2) high-temperature cycles, (3) high-humidity cycles, (4) ultraviolet (UV) radiation, and (5) saline solution; while the corrosion tests dealt with the corrosion of steel reinforcement embedded in RC columns wrapped with FRP sheets. RC columns were wrapped with carbon fiber reinforced polymer (CFRP) sheets and glass fiber reinforced polymer (GFRP) sheets and conditioned under the environmental conditions listed. After the environmental conditioning, uni-axial compression tests were conducted in order to evaluate the effects on the mechanical properties, such as column capacity, stiffness, and ductility.; The test results showed that the mechanical properties were affected due to the environmental conditioning and the corrosion of steel reinforcement, and the effects varied according to the types of environmental conditions. Based on these results, improved design guidelines for the RC columns wrapped with FRP sheet were proposed. The proposed design guidelines included an analytical model and reduction factors to account for the effects of various environmental conditions.