Review of the Robustness Evaluation and Improvement for Bridge Structures

Abstract

The concept of robustness in bridge design has received significant attention due to recent catastrophic disproportionate collapses (e.g., Mianus Bridge in Connecticut, USA and Morandi Bridge in Italy). These events have highlighted the limitations of current codified standards, which primarily focus on individual components rather than a system-based perspective for design evaluation. To address this, the existing literature has established new measures to evaluate the robustness of bridge structures applying a system-based approaches. However, a widely accepted method has not yet been identified since the performance of different bridge structures depends on various factors, such as bridge types, materials, and span lengths. Therefore, this thesis provides a state-of-the-art literature review on evaluating and enhancing robustness for preventing disproportionate collapses of bridges. The findings suggest that the probabilistic reliability-based approach is the most promising method for evaluating robustness, although lacking an applicable framework for assessing the reliability index. Moreover, the most practical approach to enhance structural robustness is improving redundancy. However, further research is still needed to establish an acceptable robustness level.