Test Study On Mechanical Performance Of High-strength Concrete Column Confined By CFRP Under Axial Load

With the wide usage of fiber reinforced polymer (FRP) in civil engineering constructions in recent years, the research of FRP reinforcing concrete structures has received significant attentions in the field of strengthening concrete structures. Compared with the classical reinforcing methods, FRP reinforcing concrete structures has many advantages such as high efficiency and high strength, convenient to construct, good resistance to corrosion and fatigue, light weight and without additional dimension, which can be widely used in many aspects such as flexure, shear, torsion, anti-seismic, and anti-corrosion constructions. Recently high-strength concrete is used more and more widely. However, it has the disadvantage that the higher the strength of concrete is, the more brittle and worse ductility the structure is, as well the more quickly the failure process is, which is quite different from normal concrete. This disadvantage can be overcome by FRP reinforcing. And its research and development has a significant value and great prospect. So far little information on the properties of FRP confining high-strength concrete structure is available home and abroad, and the information on the properties of FRP confining high-strength concrete structure under sustained load is relatively rare, which is the most common circumstance in real constructions. The main aspects of the research work are as follows:(1) Studying of the relationship between stress and strain of CFRP confining high-strength concrete columns through 13 groups of specimens subjected to axial load. Various design parameters such as amounts of CFRP sheets, width and spacing of straps have been considered. Based on the test results, a calculative formula and simplified stress-strain relationship model are provided.(2) Studying on the mechanical performance of CFRP confining high-strength concrete columns under sustained load through 12 specimens. Various design parameters such as amounts of CFRP sheets and different sustained load have been considered, and then compared the results with non-sustained load experiment. Based on the test results, a calculative formula and stress-strain relationship model are provided.