Report explores bridge analysis models across the United States

What are the quality assurance and quality control processes that underlie the design of new bridges in the United States?

The answers change from New York to California, as Dr. Serhan Guner, an associate professor in The University of Toledo's Department of Civil and Environmental Engineering, explores in a new report on behalf of the National Cooperative Highway Research Program.

Intended to benefit state departments of transportation and the civil engineers whom they contract to analyze and design bridges, the report presents existing processes in each state and the District of Columbia. It concludes by suggesting directions for future research, including the development of standardized guidelines and training and the establishment of a database for sharing bridge analysis models across state lines.

"Each state department of transportation has its own processes, and it is important to understand and learn from them," Guner said. "This report is valuable as a comprehensive look at how each state department of transportation across the country operates when it comes to quality processes for bridge analysis models."

The National Cooperative Highway Research Program is a national research program carried out through the collaborative efforts of the Federal Highway Administration, the National Academy of Sciences, Engineering and Medicine and the American Association of State Highway and Transportation Officials.

Guner, whose research expertise is in analysis and design of bridges, was selected to head this state-of-practice synthesis initiative through a competitive process.

Guner spent approximately one year completing a literature review, administering a comprehensive survey to each state department of transportation with a 100% participation rate and interviewing representatives of five selected departments of transportation as case studies.

The result is more than 100 pages of synthesis that explore the quality processes for bridge analysis and design among state departments of transportation that range in size from fewer than 10 in-house bridge engineers to more than 80.

The report parses responses to questions about written processes in place for identifying appropriately qualified in-house and contracted engineers; for choosing appropriate structural analysis methods and software; and for validating software, verifying results and reconciling discrepancies between independent computer-generated models.

"First and foremost, quality processes are important for safety," Guner said. "But the quality process also has implications in terms of cost and service life of bridges."

Guner concludes his report by identifying knowledge gaps, along with suggestions for future research to address these gaps.

Most obvious is a suggestion to develop guidelines on effective quality processes for bridge structural analysis models, and specifically on complex models known as finite element and strut-and-tie models.

He also suggests developing a standardized system of advanced training for engineers in finite element and strut-and-tie analysis, as well as seminars or training courses for engineers on commonly misunderstood concepts like verification, validation, uncertainty, error and calibration.

Finally, he suggests developing a repository for sharing analysis models, which he suggests would streamline efforts across state lines.

"Departments of transportation are making great efforts in developing bridge analysis models," he said. "A shared database would allow bridge design engineers to see what models are developed by other departments of transportation and advance them further. At the end of the day, bridge engineering is about advancements and iterative design refinements."