Experimental Study On The Mechanical Behavior Of High-strength Concrete Confined By High-strength Spiral Hoops

High spiral hoops confined high concrete has many advantages, such as enhancing strengthening, good ductility, steel saving and satisfactory economic effect. For these reasons, it has an outstanding foreground. With the quick development of building material, the high-strength material, especially high-strength concrete is used in the construction engineering widely. To improve the performance of high-strength concrete, we use the high-strength steel as the hoops of confined concrete to overcome the brittleness of concrete and improve the strength and ductility of concrete. So the selection of the paper has the important theory significance and engineering application value.Through the axial compression experiment of 35 high-strength concrete columns confined by high-strength spiral hoops, the axial compression mechanical behavior of spiral hoops confined concrete is studied in this paper. The confine effect to concrete from shapes, spacing, diameter, strength of hoops is analyzed in detail. The optimum shapes and spacing of hoops for spiral hoops confined concrete are defined. The effect to ductility from the eigenvalueλ_v of steel ratio is also analyzed in this paper. The experimental result shows that the lateral deformation of concrete was confined effectively by spiral hoops, the ultimate compressive strength was increased and the ductility was improved. The peak-stress expressions, peak-strain expressions, ultimate strain formulas and stress-strain models of spiral hoops confined concrete are obtained from experiment results and pre-research. The principle of spiral hoops confined concrete is also analyzed in this paper. On the basis of the constitutive relation models existed home and abroad, also through the experimental results, the stress-strain models of high-strength spiral hoops confined high-strength concrete are defined. Through comparing the calculated results from stress-strain models to the experimental results, it shows that the stress-strain models are reasonable and the mechanical behavior of spiral hoops confined concrete can be predicted well. It also can be found that the formula results are in good agreement with the experimental results, tend to be safety, so the formula mentioned in this paper can be used for non-linear analysis of such parts.