Improving building robustness through fuse-segmentation

Abstract

[EN] As the impacts of climate change and emerging conflicts become more and more apparent, it is undeniable that more robust building structures are required for resilient societies to be able to thrive. In fact, there has been a growing research effort over the past few decades on structural robustness and progressive collapse. As a result, several building codes now include specific provisions for improving the progressive collapse resistance of building structures. At present, almost all methods for improving structural robustness included in relevant codes rely on providing extensive continuity within a structural system to ensure that alternative load paths are available to redistribute loads supported by a structural component after its failure. Although this approach has proven to be effective in many cases, certain situations do exist for which it may increase the risk of disproportionate collapse. These include, for example, cases of large initial failure or of buildings with wide spans between columns. In such situations, the remaining parts of a structural system may not be able to find a stable state of equilibrium after initial failure. Having extensive continuity can contribute to the collapsing part pulling down the rest of the structure. A possible approach for arresting failure propagation in these situations involves segmenting building structures. In fact, there exist several examples of real occurrences when the extent of a collapse was limited thanks to a building being segmented into different parts. This includes the partial collapse of the Pentagon (Washington, 2001) and of the terminal 2E building at Charles de Gaulle airport (Paris, 2004). Although segmentation was not necessarily introduced in building design for improving robustness in these cases, they do demonstrate its effectiveness in limiting the extent of progressive collapse. However, segmentation with weak borders does interrupt continuity, which has already proven its efficiency for redistributing loads in the case of small initial failures. To overcome this limitation, there exists the possibility of using structural fuses to connect different segments of a structure. Such fuses should be able to provide continuity for normal and accidental design situations considered by current building codes but would separate building segments when failure propagation is inevitable. In fact, a novel fuse-based segmentation design approach to limit the propagation of failures in building structures is currently being developed by the Endure project thanks to a grant of €2.5 million awarded by the European Research Council. This paper presents the framework being used within this project to i) develop a performance-based approach for the design of fuse-segmented buildings, ii) design and test structural fuses for selected building types, and iii) implement and validate the performance of structural fuses in full-scale buildings.