Testing Study On The Behavior Of High-Strength Concrete Column Confined By Carbon Fiber Sheet

With the development of construction technology, high-strength concrete is used more and more widely. However, the higher the strength of concrete is, the more brittle the structure is, and the worse ductility the structure is. Hence, the high-strength concrete is disadvantage for the structure to resist earthquake. What's more, many places in China may be subjected to earthquake in the future. The technology of structures to resist earthquake is important for the research of structures to resist earthquake. Therefore, it is necessary to find a proper technology to strengthen dilapidated structures, which is both economical and effective. Also, it must meet needs to requirements of continuance and development.Recently, the technology of FRP(Fiber Reinforced Plastic) confining concrete structure has been rapidly developed. It has received significant attentions in civil engineering due to their unique properties, such as high strength-to-weight ratio, good resistance to corrosion and fatigue, convenient to construction and no additional dimension. However, most information available in our country is on the properties of FRP confining normal concrete structure. Little information on the properties of FRP confining high-strength concrete structure is available. The main aspects of the research work are as follows:1 Study of the relationship between stress and strain of CFRP confining high-strength concrete through nine groups columns subjected to axial loading. Various design parameters, such as amounts of CFRP sheets, width of straps and spacing of straps, have been considered. Based on the test results, a simplified stress-strain relationship model is provided.2. The effectiveness of CFRP sheets confining high-strength concrete columns to enhance ductility and earthquake-resistance is described. Nine reinforced concrete columns were tested under cyclic lateral load and constant axial load. Based on experiments, failure pattern, hysteresis curves, skeleton curves and displacement ductility are studied systematically.3. Study of the behaviors of CFRP reinforced high-strength concrete columns. Various design parameters, such as the quantity of continuous CFRP sheets, spacing of straps, force-high ratio of the column and loading history, are considered.4. Based on the results of the test, a simplified method to calculate displacement ductility factor is proposed. The test results showed a good agreement with analysis.