Static and Dynamic Characterisation and Seismic Performance Evaluation of Nonuniformly Corroded Concrete Bridge Columns Reinforced with Carbon or Stainless Steel 

Research aims and scopes:

This project investigates the dynamic and static behaviour of ageing reinforced concrete bridge columns with carbon steel and stainless-steel reinforcements, with explicit consideration of non-uniform corrosion patterns. The aim is to capture the effects of corrosion on column stiffness, natural frequency, and damping ratio under increasing cyclic deformation, and to provide age-dependent seismic performance assessments of RC columns with varying deterioration states. The project scope includes experimental testing, numerical modelling, and probabilistic assessment.

Main body of work:

In the first stage, large-scale quasi-static cyclic and hammer tests were carried out on both intact and corroded RC columns. The results were used to calibrate advanced numerical models in OpenSees that account for nonuniform reinforcement and concrete section deterioration, as well as the dominant failure modes of circular columns. This approach enabled accurate simulation of hysteretic behaviour across a wide range of column configurations without the need for case-specific adjustments. The study also examined the impact of corrosion on the evolution of stiffness, natural frequency, and damping under cyclic loading.

In the second stage, probabilistic seismic assessments were performed on 175 hypothetical circular RC columns, covering different failure modes. Age-dependent critical lateral drift ratios were estimated and summarised using Gaussian process regression. The results were packaged into a user-friendly MATLAB application, which provides recommended drift capacity limits for RC bridge columns of different reinforcement types, corrosion levels, and ages.

Ziliang contributed to this project in conceptualisation, numerical modelling and probabilistic analyses, and experimental and numerical data processing. He also prepared manuscripts and and visualisations, including submissions to journals and conferences.