Performance indicators for highway bridges and their integration in bridge management

Abstract

Performance indicators are key and a crucial decision tool. The uncertainties in the available information for computing the performance indicators and their changes over time impose a great challenge in the decision making process. The assessment of reliability of highway bridge structures based on component reliability leads to either over-conservatism in evaluation of redundant structural systems or to overestimation of the actual load carrying capacity of non-redundant structural systems (Hendawi and Frangopoulos 1994). However, the performance of a highway bridge structure can be evaluated by assessment of its structural system reliability (Estes and Frangopol 1999). To compute the system reliability, Estes and Frangopol (1999) and Akgül and Frangopol (2004a, b) used AASHTO guidelines to formulate limit state functions for the components of various bridge system against different failure modes. The system reliability was then computed by establishing a seriesparallel model for an assumed failure scenario for the structural systems. The shortcoming in this approach is clearly the need to assume a model for system failure. Incremental nonlinear finite element analyses (INLFEA) has recently been used in the computation of system reliability of bridge structures. Using INL-FEA accurately allows for the prediction of the resistance of the entire system. In fact using this approach, serviceability as well as ultimate limit states can be considered accordingly.