Structural Performance Evaluation of Axially Loaded Carbon and Weathering Steel Circular Concrete-Filled Steel Tube Columns under Atmospheric Corrosion

Abstract

Circular concrete-filled steel tube (C-CFST) columns are increasingly used in structural and infrastructural systems in earthquake-prone regions due to their high strength-to-weight ratio and favorable composite action. C-CFST columns rely on the confinement interaction between the steel tube and concrete core to achieve high axial capacity. However, the long-term integrity of this composite action may be influenced by deteriorating environmental conditions due to industrial and urban development. Atmospheric corrosion in aggressive environments can progressively reduce the cross-sectional area and load-bearing capacity of C-CFST columns and cause a significant threat to their structural performance. This paper aims to investigate the structural performance of C-CFST columns formed with conventional carbon steel and weathering steel under the effect of atmospheric corrosion. A comprehensive probabilistic assessment of the time-dependent axial compressive capacity of C-CFST columns over a 50-year design life was performed. A comparative structural reliability analysis between Carbon Steel (CS) and Weathering Steel (WS) exposed to an urban environment is conducted using Monte Carlo Simulation with 104 iterations. To ensure an unbiased evaluation of the empirical power-law corrosion model, the common random numbers technique is implemented. The probabilistic outcomes demonstrate that corrosion not only decreases the mean structural capacity but drastically amplifies the uncertainty (standard deviation) over time. The results based on the numerical example emphasize that incorporating sacrificial thickness or additional protective coatings during the initial design phase is required for C-CFST columns to ensure long-term structural integrity.