Risk- and sustainability-informed decision-making for durability enhancement and service life extension of steel bridges using maintenance-free steel  

PI: Dan Frangopol
Co-PI(s): David Yang
University: Lehigh University

Aging infrastructure poses substantial threat to the prosperity and sustainability of society. Bridges, as critical nodes in the transportation infrastructure, are especially crucial. In Pennsylvania, the average age of bridges recorded in the National Bridge Inventory is over 40 years ago. Many of these bridges have been servicing beyond their initial design service life. Still, these overage bridges serve millions of users every day, posing considerable risk to the functionality of the transportation infrastructure and to the safety of traffic users. Nevertheless, a total overhaul and rebuilding of all these bridges are neither realistic from a budgetary standpoint nor reasonable given that over-design is common in bridges. Therefore, sensible end-of-life (EOL) management of aging bridges, including the planning and implementation of in-depth inspection, load rating/posting, bridge rehabilitation, and, in severe cases, bridge demolition and rebuilding, is urgently needed to ensure that the risk of bridge failure be under an acceptable level.

To this end, the main objective of this project is to establish a risk- and sustainability-informed EOL decision-making framework for aging bridges in order to extend their useful service life. This objective will be achieved through a risk- and sustainability-informed intervention prioritization and a value-based EOL management that delivers high return on infrastructure investment (ROI) and long extended service life. Emphasis will be put on simply supported non-composite steel (SSNCS) bridges, considering their prevalence in PA, and their relative old age compared to other bridge types. For rehabilitation planning, this project will emphasize the use of maintenance-free steel, a locally sourced material in PA, due to its high durability performance and potentially significant cost-effectiveness from a life-cycle perspective. Ultimately, the project will benefit the Commonwealth and the Nation in solving the Grand Challenge set out by ASCE – “reducing the life-cycle costs of infrastructure by 50 percent by 2025.”