test methods. The results indicate that ER, GPR, and HCP generally correlate in defective zones (shown in the broken rectangle), showing the onset of the corrosion activity (Figure 8). The same conclusion is observed for the correlation between the IE and USW contours for the damage phase (Figure 9). Such strong correlation between multiple NDE techniques confirms the improved reliability of complementary NDE technologies to monitor the progression of corrosion leading to damage in a bridge deck. The above correlation between defec- tive zones provides for a qualitative assessment of condition a more rigorous, statistically based condition evaluation of the deck is presented in Babanajad and Jalinoos (2022). Several efforts are underway from FHWA, which is currently working with nine state trans- portation agencies to determine the feasibility and cost-benefit of incorporating NDE and SM methods into bridge deck preservation strategies. Adoption of NDE/SM information should complement data- driven decision-making systems in the selection of various preservation actions. This ongoing effort includes investigating and documenting the con- ventional NDE/SM technologies that are currently being used quantifying the value of NDE/SM using return on investment methodology and developing a model that relates NDE/SM results to the struc- ture’s condition and quantifies the associated return on investment for each maintenance and preserva- tion strategy. In addition, FHWA and Iowa DOT led an initiative to develop the framework for a bridge deck preservation portal (BDPP) intended to be widely available to engineers across the nation and widely applicable but tailorable to bridge-specific scenarios the engineers encounter. The BDPP frame- work (ElBatanouny et al. 2020) provides a system- atic approach for predicting changes to bridge deck service life by combining physical characteristics, condition assessments, and user preferences/con- straints with the application of specific bridge deck maintenance actions. When completed, the devel- oped cloud-based tool will be hosted on the FHWA’s InfoBridge website (https://infobridge.fhwa.dot.gov/). Conclusion Despite the obvious advantages, deployment of multiple complementary NDE technologies still has not gained widespread use for informed main- tenance and replacement decision-making. This is attributed to the following factors: Ñ Reliability of advanced technologies: Technological advancement has been rapid while there are few studies available on their reliability. Many NDE technologies have been well proven for local defect characterization, but their use in large-scale components is still not very clear. The standardization of methods, measurement incon- sistency among multiple NDE technologies, lack of temporal and spatial correlations for multiple datasets, lack of repeatability between multiple vendor technologies, reliability of a given method, reporting requirements, and different measurement resolution limit the capabilities of many NDE tech- niques in being integrated into routine practice. More work is underway to address these areas. Ñ Cost-effectiveness: Cost-effectiveness has been a major issue in implementing advanced tech- nologies. New technologies should provide value to owners. To augment them with routine visual FEATURE | BRIDGEINSPECTION 0 30 20 10 50 0 2500 Sound Fair Poor Serious 3200 3800 4400 (Ksi) 5000 5600 100 150 200 250 0 30 20 10 50 100 150 200 250 Figure 9. Comparative assessment of NDE technologies on damage stack: (a) USW (b) IE. 32 M AT E R I A L S E V A L U AT I O N • J A N U A R Y 2 0 2 3 2301 ME Jan New.indd 32 12/20/22 8:15 AM COURTESY: DR. NENAD GUCUNSKI, RUTGERS UNIVERSITY US W IE

inspections, these technologies should replace some components of the visual inspections or reduce the time of inspections to offset the addi- tional costs. Most advanced technologies are not yet at that stage, and there has been little focus from technology developers on this aspect. Ñ Education: Most college undergraduate students entering the workforce still do not have a formal introduction to new technologies while in school due to given educational requirements and a limit of how many courses/technologies can fit beyond fulfilling engineering fundamentals. Ñ Exposure and training: There are limited trainings available for owner agencies as part of continuing education to improve the current workforce in these technologies. There is little focus by technology developers and academic institutions in this area. Ñ Procurement: Many bridge owners do not have in-house technical staff that can keep up with technological advances and develop procurement specifications due to wide array of manufacturers and vendors offering similar equipment and services but with different features. The typical procurement methods used by owners for design and construction of bridges also may not be suitable for procurement of developing technol- ogies. The burden of longtime maintenance and fear of obsolescence also hampers the use of new technologies. Some technologies such as SM have high breakeven periods, and thus is hard for owners to justify their use due to resources needed that outweigh immediate needs. Given the challenges in implementing new technologies, FHWA and other transportation agencies have striven to improve their accessibil- ity and know-how for the underutilized technolo- gies. FHWA developed the Bridge Inspectors NDE Showcase (BINS) program (Jalinoos 2009). The purpose of the showcase is to familiarize bridge inspectors with various portable technician-driven NDE technologies such as ultrasonic testing, eddy current, ground penetrating radar, impact echo, and infrared thermography. Further, FHWA devel- oped a companion NDE web manual as an aid for the bridge community for selecting suitable NDE technology solutions for different engineering problems (Jalinoos 2008). The NDE web manual has since been expanded into the InfoTechnology web portal (FHWA 2022c) which, besides the bridge module, now includes tunnels and pavements and will soon include structural monitoring and under- ground utilities modules. Finally, for geotechnical disciplines—including concerns about foundations and subsurface characterization—FHWA has devel- oped the geophysical manual (Wightman et al. 2004) now hosted by the subsurface committee of the Deep Foundation Institute (DFI). FHWA is also working on developing procurement guidance as well as technical resources at its research and resource centers. Finally, in September 2021, the Government Accountability Office (GAO) in its report, Highway Bridges: Federal Highway Administration Could Better Assist States with Information on Corrosion Practices (GA0-21-104249), recommended that FHWA to include activities in ongoing bridge preservation efforts. Examples of such bridge preservation efforts include peer exchanges and case studies that focus on addressing the challenges states face with deter- mining the circumstances under which specific corrosion practices and materials are most effective. As such, FHWA plans to conduct two regional peer exchanges. The first peer exchange will include representative midwestern and northeastern states, which have environments with arid conditions or that experience frequent freeze/thaw cycles and use deicing chemicals on their highway bridges. The second peer exchange will include represen- tative southeast and western states which have environments that experience freeze/thaw cycles and/or have highway bridges that are exposed to a saltwater environment. These peer exchanges will focus on the states’ practices and materials used that mitigate bridge corrosion. Based on these shared experiences and lessons learned, FHWA will publish case studies and/or communicate the findings to states to improve their bridge preserva- tion programs. AUTHORS Sreenivas Alampalli: Senior Principal - Transportation, Stantec, 3 Columbia Circle, Suite 6, Albany, NY 12203 1-518- 763-1580 sreenivas.alampalli@stantec.com Frank Jalinoos: Coatings and Corrosion Laboratory Manager, Long-Term Infrastructure Performance Team, HRDI-30, Turner-Fairbank Highway Research Center, 6300 Georgetown Pike, McLean, VA 22101 1-202-493-3082 frank.jalinoos@dot.gov Raj Ailaney: Senior Bridge Preservation Engineer, FHWA Office of Bridges and Structures, Federal Highway Adminis- tration, Washington, DC 1-202-366-6749 raj.ailaney@dot.gov CITATION Materials Evaluation 81 (1): 24-34 https://doi.org/10.32548/2023.me-04292 ©2023 American Society for Nondestructive Testing REFERENCES Alampalli, S., and F. Jalinoos. 2009. “Use of NDT Technologies in US Bridge Inspection Practice.” Materials Evaluation 67 (11): 1236–1246. Alampalli, S. 2019. “Use of Nondestructive Testing in Bridge Inspection and Evaluation Practice.” FastTIMES 24 (3): 42–43. J A N U A R Y 2 0 2 3 • M AT E R I A L S E V A L U AT I O N 33 2301 ME Jan New.indd 33 12/20/22 8:15 AM