PI: Dan Frangopol

University: Carnegie Mellon University

Many of the nation's bridges are approaching the end of their design service life. In Pennsylvania, the average age of bridges recorded in the National Bridge Inventory is 40 years. Among these bridges, simply supported non-composite steel (SSNCS) bridges are considerably older than many other bridge types. According to the bridges data provided by the Pennsylvania Department of Transportation, the average age of SSNCS bridges on State Route System has reached 53 years, while over 50% of them are older than 63 years. Considering that most bridges designed in the period 1950s-1970s have a design service life of 50 years, most SSNCS bridges in PA have been servicing beyond their initial design limits. These SSNCS bridges serve an overall average daily traffic (ADT) of around 2.5 million vehicle units. Obviously, this poses considerable risk to the functionality of the transportation infrastructure and to the safety of millions of traffic users.

The main objective of this project is the life-cycle investigation on the use of novel corrosion resistant steel in new and existing bridges. The research will explore the potential and benefit of partial or full replacement of conventional carbon steel bridges with maintenance-free steel bridges. Compared to new construction, the partial or full replacement considered herein can greatly improve the life-cycle performance of bridges while significantly reducing the life-cycle cost burden upon transportation agencies. The proposed research is urgently needed. It will provide important information and guidance to Pennsylvania companies. Ultimately, the project will benefit the Commonwealth and the Nation in their commitment to solving the Grand Challenge set out by ASCE: "reducing the life-cycle costs of infrastructure by 50 percent by 2025."