Kunming University of Science and Technology
Ring section is a common form of section in engineering structure, but there exists double nonlinearity (nonlinearity of material and section width) in reinforcement calculation of concrete ring section. In the Code for Design of Concrete Structures, only the transcendental equations for the calculation of uniform reinforcement are given, which require programming and iterative solution and cannot be calculated manually, which is very inconvenient. In addition, some ring section members (such as high bridge piers, precast pipe piles, etc.) have long length, large section size and large amount of reinforcement. If uniform reinforcement is adopted, the reinforcement stress near the neutral axis is small and the economy is poor. If asymmetrical reinforcement is adopted, the stress reinforcement is arranged in the peripheral area far away from the neutral axis, which can make full use of the strength of concrete and reinforcement to improve economic benefits.Based on the constitutive relation between concrete and steel, this paper determines the range and boundary of strain variation and starts from strain. By analytical method, stress is solved by strain, and then internal force is calculated without iteration. Finally, the calculated results are drawn into a Nomo-diagram that is convenient for manual calculation of reinforcement, which is fast and convenient for calculation, and suitable for C50 or below strength concrete and annular sections with arbitrary diameters.