Compression-Bending Strength Model for Corrugated Steel Tube Confined Reinforced Concrete Section

Corrugated steel tube (CST) confined reinforced concrete (RC) sections, which consists of galvanized corrugated steel tubes infilled with concrete and steel reinforcements, provide a solution for their practical application in the outdoor and offshore corrosive environment. To investigate their compression-bending, cross-sectional behavior, a fiber model is established by treating it as a confined reinforced concrete section. The model considers the nonuniformity of concrete confinement pressure across the cross-sectional depth and tensile axial-strain concentration at the lock seam. The ultimate strength and lateral deflection of the CST confined RC sections are investigated. Further in-depth analyses are carried out to study the influence of the eccentricity ratio, geometric parameters (thickness, helical angle and corrugation profile of tubes, and reinforcing bars ratio), as well as materials strength (concrete and tube). Finally, a design method is proposed to predict the compression-bending strength of CST-confined RC sections, and its precision is verified by comparison with tests and numerical results.