Risk-based asset management framework for highway retaining wall systems using wireless structural health monitoring data

Retaining walls are important structural systems used in the construction of highways. With asset management methods for retaining wall inventories lagging those developed for highway bridges, there is a need to develop risk management methods for these critical structural systems. A major challenge is the vast inventories of retaining walls that asset managers must manage and the inherent limitations of visual inspections. This study proposes an asset management framework for retaining walls based on risk assessments using structural monitoring data. First, a long-term wireless monitoring solution is proposed to measure wall tilt and strain over long periods of time. Second, an analytical framework is developed to separate wall thermal responses from lateral earth pressures responses with the latter used to extract estimated lateral earth pressure distributions. A statistical distribution of lateral earth pressures are used in a reliability assessment of the wall to provide a measure of failure probability that can be combined with failure consequences to estimate asset risk. To illustrate the proposed methodology, a reinforced concrete cantilever retaining wall panel is selected for long-term structural health monitoring. A wireless structural health monitoring system is installed to measure the tilt, strain, and temperature response of the wall continuously over 15 months. The study reveals the wall exhibits strong diurnal and seasonal variations offering insight into wall behavior under operational conditions. Hypothesized levels of corrosion in the steel reinforcement at the base of the wall are explored to estimate the wall reliability. Even under the assumption of 20% reinforcement section loss, the monitored wall was found to have a reliability index well above 3.0.