Performance Evaluation of Damage-Integrated Composite Steel Girder Highway Bridges

The safety and condition of transportation infrastructure has been at the forefront of national debates in recent times due to the catastrophic bridge failures occurred in the United States, but the issue has been a longstanding challenge for transportation agencies for many years as resources continue to diminish. The performance of this infrastructure has a direct influence on the lives of most of citizens in developed regions by providing a critical lifeline between communities and the transportation of goods and services, and as a critical component of the transportation network, bridges have received a lot of attention regarding condition assessment and maintenance practices. To date, several inspection methods and monitoring techniques have been developed and used by the bridge owners to monitor the in-service behavior and detect different sourced of damage and deterioration in bridge structures. Despite successful implementation of these methods, what is still lacking is a fundamental understanding of the system behavior in the presence of deteriorating conditions that can be used to estimate the remaining service life of the structure and facilitate the preservation decision-making process.
This research project aims to present a performance-based numerical modeling framework that can be used to characterize the behavior of in-service bridge superstructures under the impact of common deteriorating mechanisms. Representative numerical models were generated based on available experimental data in literature, ranging from basic levels of intact bridge components to more complicated levels of bridge superstructural systems with both intact and damaged configurations. Both material and geometric non-linearities were included in the corresponding computational analyses to describe the behavior and failure characteristics of the simulated structures and their sub-components. Critical to this modeling approach is the strategy to leverage simulation techniques and appropriately integrate the effects of existing deteriorating conditions into the measure of system performance. The validity and accuracy of the proposed modeling approach were evaluated through comparisons of the numerical results to those obtained from the corresponding experimental investigations.
Upon validation, the methodology was extended to study the impact of corrosion in steel girders and subsurface delamination in reinforced concrete decks on the ultimate capacity, redundancy, and operational safety of representative in-service composite steel girder bridges. Results from this investigation demonstrated that corrosion in steel girder may significantly influence the capacity and performance of the composite steel bridge superstructures; while subsurface delamination would reduce the overall system ductility due to local premature failure mechanisms associated with the reinforced concrete decks. It should be noted that although this investigation is limited to composite stringer bridges, the proposed approach is generic and can be extrapolated to assess the functionality of other types of structures under various in-service conditions. It is expected that the proposed framework for evaluating system behavior will provide a critical first step for establishing a critical linkage between design, maintenance, and rehabilitation of highway bridges, which are uncoupled in current infrastructure decision-making practices.