Site Reconnaissance
Document indicators of corrosion and areas of satisfactory performance
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The Challenge
- Needed to assess the condition and remaining service life of 32-year-old MSE wall reinforcements
- Uncertainty about corrosion posed a potential risk to wall performance and longevity
- Determining broader implications for similar structures across the state
Metallically reinforced Mechanically Stabilized Earth (MSE) walls are designed for long service life, however, the durability of their reinforcements is a key factor influencing their long-term performance. When buried in soil, reinforcing elements are vulnerable to corrosion due to electrochemical interactions with the surrounding environment.
WisDOT required a data-driven evaluation of an MSE wall to understand current performance, root causes of observed deterioration, and remaining service life of the structure.
The Solution
Geocomp conducted a comprehensive investigation to 1) Evaluate reinforcement condition and backfill geotechnical/electrochemical properties. 2) Estimate remaining service life of the structure. 3) Assess the state’s design and maintenance practices to improve long-term durability.
The study’s findings emphasized the critical impact of pavement distress and salt intrusion on the deterioration of MSE wall reinforcements. Deterministic and probabilistic stability analyses indicated that internal failure was likely within the design service life of the structure. The deterministic analysis showed that while the original design had an adequate factor of safety against slope stability, corrosion would reduce it to below 1.3 within approximately40 years after construction. The probabilistic analysis indicated a failure probability exceeding 1% at 55 years.
