Performance Evaluation of Damaged Integrated Girder Bridges.

摘要

The safety and condition of the national transportation infrastructure has been at the forefront of national debates in recent times due to 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 ASCE’s 2013 report card for America’s Infrastructure assigned in-service bridges a score of C+, which reflects the extent of deteriorating conditions and deficiency of the national aging infrastructure network. Currently, transportation officials rely heavily on experienced-based practices to make decisions regarding maintenance and preservation of the bridge inventory. Several inspection methods and monitoring techniques have been developed and used by the bridge owners to monitor the in-service behavior and detect deteriorating conditions. Despite successful implementation of these methods, the lack of a rational understanding of the system-level behavior of in-service structures, especially in the presence of damage and deterioration, makes resolving this problem even more complicated. This constraint, coupled with limited resources and the vast network of existing structures in service, highlights the need to develop systematic strategies to help engineers better understand the system performance and estimate the remaining service life of these structures, while facilitating and supporting maintenance/preservation decision making process. This research project aims to present a performance-based numerical modeling framework that can be used to evaluate the behavior and identify the failure characteristics of in-service bridge superstructures under the impact of common deteriorating mechanisms. Representative numerical models, ranging from basic levels of intact bridge components to more complicated levels of bridge systems with both intact and damaged configurations, were generated based on available experimental data in literature. Critical to this investigation is the strategy to leverage simulation techniques and appropriately integrate the effects of existing deteriorating conditions into the measure of system performance. Upon validation of the proposed simulation approach, the methodology was implemented to study the performance parameters, including ultimate capacity, redundancy, and operational safety, of representative in-service composite steel girder and prestressed concrete girder bridges under the of various damage conditions. It is expected that the developed framework will provide a first step for establishing a critical linkage between design, maintenance, and rehabilitation of highway bridges, which are uncoupled in current practices.