Impact of Rebar Corrosion Rates on Mechanical Performance of Offshore Tunnel Linings

Abstract

In this paper, a parametric study of the effect of corrosion rates on the structural performance of offshore tunnels was conducted. Through experimental studies, the results of pull-out tests show that corrosion rates of less than 1% can actually improve bond strength, further narrowing the range of critical corrosion rates for commonly used reinforcement bars to between 1% and 2%. The test results were also fitted to the bond interface tangential stiffness and tangential strength decay equations to provide data support for numerical simulations. From the numerical simulation, the bond-slip between the corroded reinforcement and concrete was investigated using the fitted equations. Results have verified the correctness of the simulation with the experimental results, and the bond strength with a higher corrosion rate could be predicted based on the equations. In addition, the tunnel lining model was also used to study the performance of the offshore tunnel structure after the corrosion of reinforcement at the tunnel and the results showed that after the corrosion of the right knee, the surface stresses at the right-knee, haunch, and shoulder positions would change accordingly, and when the corrosion rate reaches 3%, the safety coefficient of the right-knee position decreases by 7.8%. When the corrosion rate of the right-knee position is 15%, the safety coefficient of the right- and left-knee and the right-haunch positions is less than the standard value, indicating that the safe bearing capacity is lost.