Life-cycle civil engineering addresses, among other things, the growing number of deteriorating bridges and the associated economic challenges. As a consequence, government bodies, infrastructure and bridge owners as well as industry request objective and rational performance indicators for classification and intervention planning in structural engineering. This paper focuses on a methodology for analysing the damage-based robustness margins of bridge systems under traffic loading. In particular, a series of emergent deterioration-based damage scenarios are compared with the actual or virgin state in terms of loadbearing capacity and serviceability. Non-linear finite element analysis based on a detailed 3D model has a high potential for capturing the available bridge capacity for different degradation phenomena and levels, serving as an input for further reliability-based performance indicators. Notwithstanding, costs associated with fully probabilistic assessment measures are still prohibitive despite technological advances and new methods of reducing the sample size in Monte Carlo computations. In addition, considering the large uncertainties and imprecision involved, it is imperative that probabilistic schemes are preferred over deterministic assessments.
The objective of this article is to present strategies for robustness-based performance assessment using non-linear modelling and to discuss relevant reliability-based quantities and performance indicators in relation to structural damage using the example of specific degradation events in an existing prestressed box girder bridge. Furthermore, some strategies are developed on the basis of the new approach for general complex engineering structures.