InfrastructureChanging bridge fabrication and inspection practices

“The devil is in the details,” said William Wright, an associate professor of civil and environmental engineering at Virginia Tech who was once named the Engineer of the Year by the Federal Highway Administration. The agency cited him for his work on “ high performance steel that led to reduced initial cost, lower maintenance, and longer life for many new bridges nationwide,” according to the highway administration’s press release announcing his award.

A Virginia Tech release reports that Wright is concerned about size, especially when it relates to how materials will perform in structures where failures might lead to catastrophes. As today’s engineers investigate the rebuilding of much of the nation’s infrastructure, a lot of which was constructed in the 1950s, they are using much improved materials and analysis tools.

“These advances can be combined to greatly reduce the risk of failure of steel bridges by brittle fracture,” Wright said.

Based on his expertise in engineering and materials for bridge spans, the Virginia Tech civil engineer predicts his new work on a fracture control plan for steel bridges “promises to change bridge fabrication and inspection practices.”

Currently the highway administration requires more intensive inspection for structures that are at risk from fracture failure, a major cost factor for bridge maintenance budgets. The current fracture control plan was developed in the 1960s and has not kept up with advances in materials and computerized system analysis.

Wright is in the initial stages of this new study, funded by the Transportation Research Board, to identify critical members in steel bridges that need to be protected from failure by fracture.  Working with him is Robert J. Conner of Purdue University’s Civil Engineering Department. Together, they received a $350,000 grant to develop an improved method to determine the structural consequence if brittle fracture occurs.

“Most bridge engineers now have the capability of performing a particular evaluation — a three-dimensional elastic finite element system of analysis of bridges. This is a powerful tool that provides a platform for studying internal load re-distribution in damaged structures such as bridges. However, the problem remains that the ultimate strength of a structural system made of steel and concrete is a highly non-linear problem,” Wright said. There is limited information available about the ultimate strength of bridge systems.

Wright refers to the problems as “non-linear” because they can involve combinations of steel yielding, steel buckling, concrete crushing, and connection failure. The elastic three-dimensional method