**9.1 Condition assessment of ground-mount cantilever highway weathering-steel overhead sign structures**

Weathering steel (WS) is a high-strength, low-alloy steel and best known under the trademark COR-TEN or Corten steel. There are approximately 100 WS bridges and numerous WS overhead sign structures (WSOSSs) throughout the State of West Virginia, and inspection of these WS structures is essential to maintain public safety. Zatar and Nguyen conducted an expansive work that aimed at assessing 82 WSOSSs in the Charleston Interstate System in West Virginia [32]. A total of 26 comprehensive inspection forms were developed to objectively evaluate the current condition of 11 general types of sign structures. This part of the project focused on analyzing 25 single-armed and double-armed ground-mount cantilever WSOSSs (GMC-WSOSSs). **Figure 4** shows the locations of the overhead sign structures along I-64, I-79 and I-77 in Charleston, West Virginia.

A reliable ultrasonic testing technique was used to examine key components of the sign structures while the other components were inspected by visual inspection technique [33]. A rating methodology was developed to evaluate the sign structures at both the element level and their overall condition. The element condition was rated based on the developed rating criteria and score. The overall condition of each sign structure was then evaluated by the ratio between the total score of each structure and its maximum possible total score. It was concluded that all the GMC-WSOSSs performed relatively well after more than 40 years of service and exposure to moist weather condition of Kanawha County (climate zone 4A). The study found out that 52 percent of sign structures were found to be in fair condition and 48 percent were in good condition [33]. The rating system assisted the West Virginia Department of Transportation in making rational decisions about whether there is a need to repair or replace at-risk elements, connections, of these sign structures.

*Environmentally Influenced Risk and Sustainable Management of State Controlled... DOI: http://dx.doi.org/10.5772/intechopen.98232*

### **9.2 Performance of dual-shoulder-mount-truss highway weathering-steel overhead sign structures**

Zatar and Nguyen conducted a study that focused on evaluating 15 dual-shouldermount-truss weathering steel overhead sign structures (DSMT-WSOSSs) in Charleston Interstate System in West Virginia [34]. A non-destructive testing technique was used to examine key components of the sign structures while the other components were inspected by visual inspection. **Figure 5** shows one of the dual-shoulder-mount-truss overhead sign structures. A rating methodology was developed to evaluate the sign structures at both the element level and overall condition. The element condition was rated based on developed rating criteria and score. The rating system assisted the West Virginia Department of Transportation in making rational decisions about whether there is a need to repair or replace at-risk elements, connections, or structures. All the DSMT-WSOSSs performed relatively well after four decades of service and exposure to moist weather condition of Kanawha County. Eighty seven percent of the sign structures are in fair condition and thirteen percent are in good condition [34].

## **9.3 Risk Management and rehabilitation of transportation infrastructure with FRP wraps**

Concrete highway bridges in the State of West Virginia are exposed to the deleterious effects of environmental attacks, leading to degradation of these bridges as they age. The concrete deteriorates at the reinforcement level, leading to cracking and spalling of the concrete owing to volume increase of the steel reinforcement. According to 2017 National Bridge Inventory (NBI) database [9], West Virginia has 7,228 highway bridges and 19 percent of these bridges (1,372 bridges) were rated as structurally deficient. Of all the highway bridges in West Virginia, 1,394 bridges (19.3 percent) were rated as functional obsolete.

One solution to overcome steel corrosion in concrete for new construction is to use Fiber-Reinforced Polymer (FRP) materials for internal reinforcements instead of steel reinforcement. More significant is the beneficial application of FRP for structural rehabilitation of deteriorated concrete bridge structures. FRP composite materials in the form of fabrics, laminates, and bars have been externally bonded to concrete structures to increase structural capacity and provide longer service-life [26]. The application of this technology in practice has been highly successful [26].

**Figure 5.** *Dual-shoulder-mount-truss weathering-steel overhead sign structures.*

Overall condition of all highway bridges in the State of West Virginia are reported where the data is extracted from the latest National Bridge Inventory by U.S. Department of Transportation and Federal Highway Administration. A few case studies for the use of FRP composites for rehabilitating bridge structures in West Virginia were examined. **Figure 6** shows two bridges in the inventory of West Virginia Department of Transportation. Cost of FRP-wrap projects by West Virginia Department of Transportation is addressed [35].
