Causal models for the forensic investigation of structural failures

e structural collapses are rare events that are characterized by complex dynamics: the identification of their causes and the explanation of their developments are not straightforward processes and depend on numerous different factors. A fundamental aspect is that, even if sometimes it is possible to identify the trigger that have materially caused the collapse, usually there is a complex background of situations that have made the event possible and that need to be accurately analyzed. The investigation of the interrelated aspects and concurrent causes is a fundamental task to assign conveniently the civil and criminal responsibilities. Starting from these considerations, the aim of this paper is to present some concepts that, in theAuthors’opinion, constitute a basisfortheframeworkoftheinvestigationactivities.Inthefirstpartoftheworktwoconceptsarediscussed.The first one is the concept of structural complexity, which is an attribute of the civil constructions that are characterized by significant interactions, strong nonlinearities, and large uncertainties.The second concept regards the extension to the Civil Engineering field of a model for the development of failures proposed by Reason (Swiss Cheese Model, 1990). In the second part of the paper some operational approaches are briefly introduced: the breakdown of the problem and the analysis of the timeline; they are essential tools for the assignment of the various responsibility profiles.At the end of the contribution, the concept of structural dependability is recalled as an antidote to avoid failures providing high-quality structural design.