Title: Cellular Automata for Corrosion in Carbon Fiber- Reinforced Polymer-Strengthened Bridge Columns

Author(s): Jun Wang and Yail J. Kim

Publication: Structural Journal

Volume: 121

Issue: 1

Appears on pages(s): 5-20

Keywords: carbon fiber-reinforced polymer (CFRP); cellular automata; column; corrosion; model; rehabilitation; strengthening

DOI: 10.14359/51739181

Date: 1/1/2024

Abstract:
This paper presents the durability modeling of bridge piers subjected to corrosive environments including atmospheric, splash, and submerged conditions for a service period of 100 years. Two types of reinforced concrete columns are used—cast-in-place and accelerated bridge construction (ABC)—and their time-dependent performance is predicted by von Neumann’s square lattice in conjunction with a novel evolutionary mathematics approach called cellular automata. The capacity of the corrosiondamaged columns is upgraded using carbon fiber-reinforced polymer (CFRP) sheets. Depending on the concrete strength and construction method, chloride migration mechanisms are evaluated to elucidate the variation of diffusion coefficients, chloride concentrations, and other corrosion-related issues for those columns with and without CFRP confinement. For the first 30 years, the chloride diffusion of the ABC column is slower than that of the cast-inplace column; otherwise, no difference is noticed. Under the splash condition incorporating periodic wetting-and-drying cycles, chloride concentrations remarkably increase relative to other exposure environments, particularly for the cast-in-place column. The development of corrosion current density is dominated by the pore structure of the concrete, and the corrosion initiation of the ABC column takes 4.3 times longer compared with its cast-in-place counterpart. At 100 years, the capacity of the cast-in-place and ABC columns decreases by 28.1% and 23.2%, respectively, primarily due to the impaired concrete near the degraded reinforcing bars in a corrosion influence zone. The columns’ responses are enhanced by CFRP confinement in terms of toughness, energy dissipation, loadcarrying capacity, and load-moment interactions.