Progressive collapse and robustness of buildings and bridges

Overview

Building and bridge collapse result in severe consequences, including the tragic loss of lives, significant economic harm, disruption of critical infrastructure, and lasting effects on public safety and community resilience. These collapses often originate from localised failures that propagate to the rest of the structural system, leading to disproportionate damage.

The presentation will explore the complex factors behind such a phenomenon by analysing case studies and findings from large-scale experimental campaigns. These include tests on masonry arch vault structures subjected to local differential settlement, a novel shoring system design to prevent failures during construction, the robustness assessment of a “field-extracted” steel truss bridge, and column removal tests on flat slab and precast buildings.

The most recent full-scale test involved the partial collapse test of a unique, purposely built precast building to validate the newly developed fuse-based segmentation approach to arrest collapse propagation. Inspired by how lizards shed their tails to escape predators, this approach ensures sufficient continuity to redistribute loads after small failures, complying with current building codes.

However, specific components are engineered to separate during a collapse, preventing further damage beyond the initially affected areas. These large-scale experiments provide critical insights into the realistic (systemic) interactions of different structural elements, often overlooked (or simplified) in reduced-scale tests. Such insights will be invaluable in exploring and potentially developing novel design approaches for improving the resilience of our buildings and bridges.