The Arizona Department of Transportation (ADOT) retained NCS as part of their on-call contract to prepare a condition assessment of 50 side-hill retaining walls along a 10 mile long stretch of US 191 (Coronado Trail) in Greenlee County north of Morenci.

The walls along US 191 were originally built in the early 20th Century and were mostly dry-stacked walls using local materials such as andesite, granite, ryolite, obsidian and others. Over the years, the roadway was realigned horizontally as well as vertically. This has posed additional load on the walls. Virtually all walls inspected show different levels of distress ranging from bulging to in-plane and out-of-plane deformation of stones.

NCS developed a detailed form and procedure for the evaluation and inventory of these walls, including a comprehensive description of their condition and any deformations or problems. The field investigation was a joint effort between NCS, ADOT, RS Engineering and others. The report which was prepared by NCS will assist ADOT in determining what walls they would like to fix, and other items related to these walls that need consideration when it comes to improving the highway.