Comparison of Three Retaining Wall Condition Assessment Rating Systems

In general, the nature of permanent earth retaining structures (ERSs) in highway engineering is well suited to the concept of asset management as a valuable tool for operational efficiency and cost control. Earth retaining structure failures can be detrimental to the roadway and the surroundings, and may pose potential hazards to the safety of the public. Work in this paper utilized field survey results from 11 ERSs to illustrate the disadvantages of using a numerical rating system that relies on a single average number, and the applicability of the alternative system presented herein. The ERSs evaluated include mechanically stabilized earth (MSE), soil nail, anchored, gravity, and cantilever earth retaining wall types. Results indicated that the use of a single-value numerical rating can mask deficiencies in ERS elements that are critical to the stability and function of the ERS system. In addition, the identification of specific elements in distress is not apparent when using such an approach. An alternative two-part rating system provides a summary rating that articulates both the condition of the ERS and identifies potential problems with specific ERS elements. As transportation agencies attempt to align with Moving Ahead for Progress in the 21st Century Act (MAP-21), a two-part condition rating system is recommended to better execute an ERS asset management program and integrate it into a systemwide plan.