Technology innovation in sensing, computing, and robotics has significantly bolstered the transportation sector over the past decades, from intelligent construction to nondestructive evaluation (NDE). Technology is a primary driving force that provides advancements to support the Nation’s highway infrastructure assets that span more than 2.7 million miles of paved roads, 620,000 highway bridges, and 470 tunnels. While technologies have changed dramatically over the years, the core mission of the Federal Highway Administration remains to serve as a pillar of safety, strength, and efficiency for surface transportation. In alignment with FHWA’s mission, the FHWA NDE program is dedicated to conducting state-of-the-art research, development, and implementation of emerging NDE technologies to assess the Nation’s highway infrastructure assets.

After collaborating closely with stakeholders such as State departments of transportation (DOTs), American Association of State Highway and Transportation Officials (AASHTO), Federal agencies, industry, and researchers, the FHWA NDE program recognized that introducing and researching emerging NDE technologies within the highway infrastructure domain was not a simple research challenge. Instead, the research required a sophisticated understanding of engineering needs in daily operation and management; technology integration and development; and partnership across Government, academia, and industry. In response, the FHWA NDE program has formulated a strategic plan to guide the collaborative efforts and program actions.

Motivation for CHARISMA

One strategic initiative of the FHWA NDE program was to develop the FHWA InfoTechnology™ platform, which is a Web-based information platform that can help practitioners select practical NDE solutions for their engineering needs. It provides high-level introductions to NDE technologies such as visual, acoustic, electromagnetic, electrochemical, and other testing methods. This platform links various engineering needs in the condition assessment of highway infrastructure assets, such as delamination in concrete and corrosion in steel, to suitable and applicable NDE technologies.

In addition, the FHWA NDE program recognized a lack of NDE standards and technical guidelines in procuring NDE services for State and Federal agencies, which could result in large performance variations across technology and service providers. Without testing standards in place, uncertainty exists whether the performance variation is due to inconsistent implementations of an NDE technology or human factors during operation. Mitigating human factors during operation may be achieved by setting personnel requirements for certifications or using robotics. To address consistent application of NDE, FHWA is developing guidelines to streamline the procurement process for NDE services and working to ensure a consistent implementation of NDE technologies across vendors.

In 2022, to promote collaboration and develop NDE standards, the FHWA NDE program launched the Collaborative Highway Asset Research: Integrated Sensor-Model Application (CHARISMA) project. CHARISMA is an open-source software platform that facilitates the analysis and visualization of NDE and infrastructure inspection data and fosters collaboration among Government agencies, academia, and industry.

This ongoing project at FHWA’s Turner-Fairbank Highway Research Center (TFHRC) aims to foster highway research innovations and the development of NDE standards. The FHWA NDE program is working closely with collaborators from AASHTO, ASTM International, the American Society for Nondestructive Testing (ASNT), and other communities toward developing NDE standards and technical references. For instance, the FHWA NDE program has partnered with the ASTM digital imaging and communication in NDE (DICONDE) committee to establish a standardized data format for NDE data storage.

CHARISMA Design and Prototype

CHARISMA’s design process consists of two equally important functions: one performed by the FHWA NDE program and the other by the NDE community, including technology developers and researchers. The FHWA NDE program shares data and algorithms produced in house and from sponsored research projects. The role of the NDE community is to use the work and, because it is open source, enhance it if needed. The interaction is an iterative process that aims to converge well-accepted NDE practices, which will be proposed as NDE standards to AASHTO, then ASTM International, and ASNT.

CHARISMA currently uses a GitHub repository to share algorithms produced by the FHWA NDE program. The repository is open to the public, ensuring free access and transparency to the NDE community. The repository now hosts algorithms of five popular NDE technologies used for concrete and steel testing: impact echo, ground penetration radar (GPR), phased array ultrasonic testing, half-cell potential, and electrical resistivity. Readers may refer to the FHWA InfoTechnology website (see Resources sidebar) for introductory descriptions of each NDE technology. The GitHub repository will be regularly updated.

The FHWA NDE program team recognizes that transparency and reproducibility are two important factors in advancing NDE practices, in addition to other equally important factors such as ease of use, the ability for nonexperts to interpret the data, and costs. Thus, CHARISMA provides validated source code so that users can generate transparent and reproducible NDE results. In addition, CHARISMA contains case studies that provide necessary information regarding:

• How to set up CHARISMA.
• How to use CHARISMA for NDE data analysis.
• How to understand the source code, such as the description of each parameter.

For example, one case study conducted at TFHRC involves using GPR for rebar mapping in concrete bridge decks. The basic principle of GPR for rebar mapping involves sending a short pulse of electromagnetic wave into a testing subject. The received reflection wave analysis contains rich information on the testing subject, including the rebar location. Processing GPR data typically requires multiple steps of sophisticated data analysis. CHARISMA provides all source codes for the necessary steps to transform GPR raw data into processed information on rebar location. The FHWA NDE program team validates the source codes by applying the algorithm to process NDE data collected from laboratory testing and field inspections.

Next Steps

Moving forward, CHARISMA plans to expand its case study series and technology pool, including sharing advancements in artificial intelligence (AI) research to aid defect mapping and other infrastructure applications. Ongoing AI research conducted at the FHWA NDE Laboratory involves fabricating multiple concrete specimens with pre-embedded defects, which can provide high-quality labeled NDE data to train and validate various AI models. CHARISMA will share these valuable resources with the NDE community to advance future analysis methods and AI research.

“Through CHARISMA, the FHWA NDE program aims to collaborate with stakeholders, share knowledge, and drive innovation in the field of NDE technologies, ultimately leading to enhanced infrastructure assessment and management practices,” says Director of the Office of Infrastructure Research and Development, Dr. Jean Nehme. This collaboration is imperative to develop standardized NDE data collection, storage, analysis, and interpretation. Dr. Nehme continues, “This platform could be a valuable resource for researchers, practitioners, and other stakeholders involved in the evaluation and management of highway infrastructure.”

In addition, CHARISMA represents a crucial step toward standardized NDE practices essential for maintaining consistent quality in NDE services and fostering innovation in highway infrastructure research. Shane Boone, senior vice president of NDE at Bridge Diagnostics Inc., states, “Through collaborative efforts, CHARISMA aspires to drive advancements in NDE research, improve infrastructure assessment practices, and contribute to the overall efficiency and safety of our highway systems.” The FHWA NDE program will continue to work with AASHTO, ASTM International, ASNT, and other organizations to develop standardized NDE practices.

CHARISMA is built with transparency. “By establishing an open and collaborative environment, CHARISMA strives to facilitate knowledge sharing, innovation, and the effective utilization of NDE technologies across the industry,” says Anne Rearick, director of bridge management for the Indiana DOT. The FHWA CHARISMA program serves as a cornerstone of advancing NDE in the daily operation and management of highway infrastructure.

Hoda Azari is the manager of FHWA’s NDE research program and NDE Laboratory. She holds a Ph.D. in civil engineering from the University of Texas at El Paso.

Heng Liu is a contracted subject matter expert working in FHWA’s NDE Laboratory. He holds a Ph.D. in civil engineering from the University of Maryland, College Park.

Steve Yang is a contracted data analyst working in FHWA’s NDE Laboratory. He holds a Ph.D. in material science from the University of California, Riverside.

Disclaimer: FHWA and all its offices and units do not endorse products or manufacturers. Trademarks or names appear in this article only because they are considered essential to the objective of the document.

For more information, visit:
https://highways.dot.gov/research/laboratories/nondestructive-evaluation-laboratory/ongoing-projects, or contact Hoda Azari at 202–493–3064 or Hoda.Azari@dot.gov.