A review & critique of optimal fail-safe structural design

Structural material optimization holds great promise for reducing the embodied carbon in future infrastructure. However, optimized solutions typically lack robustness and may be susceptible to disproportionate collapse under damaging events such as blasts, collisions, or material corrosion. Fail-safe optimization offers a solution by balancing material efficiency with the ability to meet design requirements after a defined damage event. This paper reviews the state-of-the-art in fail-safe optimization, identifying current knowledge gaps and evaluating methodologies against existing guidelines for fail-safe design. A brief overview of fail-safe and collapse-resistant design is included to contextualize the comprehensive summary of the current literature. Key findings highlight the need for further investigation into buckling failure, allowing partial collapse, buildability aspects and the role of bending within fail-safe frame optimization. Additionally, a significant gap is identified between the types of analysis recommended in fail-safe design guidelines and those used in optimization tools, with the latter often neglecting non-linear and dynamic effects. To address this disconnect, the paper discusses optimization algorithms and techniques through the lens of incorporating more advanced analysis. This review aims to advance the development of fail-safe optimization, guiding improvements in current tools to enhance structural efficiency and safety against life-threatening events.