Strength of Normal Cross-Sections of Bending Tubular Concrete Elements With Spiral Reinforced Concrete Compression Zone

A method is proposed for calculating the strength of normal sections of a bent element in the form of a rectangular tube-concrete beam, which may have indirect reinforcement of the compressed zone in the form of a spiral. The technique is based on a nonlinear deformation model and makes it possible to determine the stress-strain state of a beam as it is loaded with a gradually increasing load. The sequence of constructing a diagram of concrete deformation under conditions of gradually increasing lateral pressure on it from spiral reinforcement is described. The developed model makes it possible to calculate beams with various structural designs. A comparison of the calculated and experimental values of the maximum bending moments for three types of pipe-concrete beams showed their good agreement.