Controlled failure: The building designed to limit catastrophe

nature video
May 15 2024

Catastrophic building collapse can have many causes, but the outcome is all too familiar; a loss of lives and the destruction of infrastructure that can have a long lasting effect on a community.

Current guidelines suggest extensive structural connectivity within a building is the best way to prevent disaster. This allows for a redistribution of weight should part of a structure be damaged. But in certain circumstances, this interconnectedness can be a building's downfall. With a large enough initial failure, collapsing parts of the building can pull down the rest of the connected structure.

So this team of researchers took a new approach, focusing not only on preventing collapse, but also managing failure if it happens. Their idea is inspired by how some lizards shed their tails to escape being eaten by a predator - a tactical sacrifice.

They call it hierarchy-based collapse isolation, and they tested their theory using an experiment two storeys high.

Read the paper: [article link and excerpt posted below]

Arresting failure propagation in buildings through collapse isolation

Nirvan Makoond, Andri Setiawan, Manuel Buitrago & Jose M. Adam
Nature volume 629, pages 592–596 (2024) Cite this article

Abstract

Several catastrophic building collapses1,2,3,4,5 occur because of the propagation of local-initial failures6,7. Current design methods attempt to completely prevent collapse after initial failures by improving connectivity between building components. These measures ensure that the loads supported by the failed components are redistributed to the rest of the structural system8,9. However, increased connectivity can contribute to collapsing elements pulling down parts of a building that would otherwise be unaffected10. This risk is particularly important when large initial failures occur, as tends to be the case in the most disastrous collapses6. Here we present an original design approach to arrest collapse propagation after major initial failures. When a collapse initiates, the approach ensures that specific elements fail before the failure of the most critical components for global stability. The structural system thus separates into different parts and isolates collapse when its propagation would otherwise be inevitable. The effectiveness of the approach is proved through unique experimental tests on a purposely built full-scale building. We also demonstrate that large initial failures would lead to total collapse of the test building if increased connectivity was implemented as recommended by present guidelines. Our proposed approach enables incorporating a last line of defence for more resilient buildings.

Main

Disasters recorded from 2000 to 2019 are estimated to have caused economic losses of US$2.97 trillion and claimed approximately 1.23 million lives11. Most of these losses can be attributed to building collapses12, which are often characterized by the propagation of local-initial failures13 that can arise because of extreme or abnormal events such as earthquakes13,14,15,16, floods17,18,19,20, storms21,22, landslides23,24, explosions25, vehicle impacts26 and even construction or design errors6,26. As the world faces increasing trends in the frequency and intensity of extreme events27,28, it is arguably now more important than ever to design robust structures that are insensitive to initial damage13,29, irrespective of the underlying threat causing it.

Most robustness design approaches used at present8,9,30,31 aim to completely prevent collapse initiation after a local failure by providing extensive connectivity within a structural system. Although these measures can ensure that the load supported by a failed component is redistributed to the rest of the structure, they are neither viable nor sustainable when considering larger initial failures13,25,32. In these situations, the implementation of these approaches can even result in collapsing parts of the building pulling down the rest of the structure10. The fact that several major collapses have occurred because of large initial failures6 raises serious concerns about the inadequacy of the current robustness measures.

Traditionally, research in this area has focused on preventing collapse initiation after initial failures rather than on preventing collapse propagation. This trend dates back to the first impactful studies in the field of structural robustness, which were performed after a lack of connectivity enabled the progressive collapse of part of the Ronan Point tower in 1968 (ref. 33). Although completely preventing any collapse is certainly preferable to limiting the extent of a collapse, the occurrence of unforeseeable incidents is inevitable34 and major building collapses keep occurring1,2,3.

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