Seismic performance of corroded reinforced concrete bridge piers
Thesis DisciplineCivil Engineering
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
The impact of general and pitting corrosion on the effective mechanical properties of reinforcing bars under monotonic tensile loading was explored experimentally. Reduction in the effective mechanical properties of steel reinforcement due to pitting corrosion was found. A novel methodology was used to develop corrosion-induced deterioration models for steel reinforcement embedded in concrete, based on comparing the configuration of mass loss in corroded bare reinforcement and reinforcement corroded while embedded in concrete. In this method an advanced 3D scanning measurement technique was employed to scan the surface of corroded bars. The impact of corrosion pattern was used to develop an analytical model to predict tensile behaviour of corroded steel reinforcement embedded in concrete. The corrosion process was simulated in a laboratory environment using an accelerated corrosion procedure. A deterioration model for cracked concrete cover due to reinforcement corrosion was developed, based on experimental compression tests on concrete core samples and statistical normal distribution. The concrete core samples were taken from noncorroded and corroded full-scale reinforced concrete columns. The effects of corrosion on the stress–strain response of confined concrete subjected to reinforcement corrosion were experimentally investigated. An analytical model based on the deterioration models developed in this study was used to predict the stress–strain response of confined concrete due to reinforcement corrosion. The analytical model was validated using the experimental results. The results of more than 100 corroded bare steel reinforcement columns, and 20 corroded full-scale reinforced concrete columns were analysed in order to develop the deterioration models in this research. The deterioration models developed for materials and the model developed for confined concrete subjected to reinforcement corrosion were then used to numerically investigate the impact of corrosion on the nonlinear pushover response of bridge piers subject to corrosion. Parametric studies were carried out to investigate the effects of important parameters on the moment–curvature or force–drift response of the corroded bridge piers. The quasistatic cyclic response of three large-scale precast bridge piers that emulate the behaviour of cast-in-place (ECIP) piers through the formation of plastic hinges in the piers were experimentally investigated. Development of advanced deterioration models due to corrosion, and implementing the models to evaluate the structural response of corroded bridges under seismic loading significantly improve the durability design approach. Moreover, they help to more accurately assess the condition of existing bridges subjected to both seismic loading and corrosive agents. The models can also improve the durability design methodology of RC structures. The results of this research will help bridge managers and owners to develop a rigorous maintenance strategy to evaluate and predict the performance of their bridge network and will also help engineers to optimise the life-cycle design of reinforced concrete bridges subjected to earthquakes and corrosion.