Temporary Housing and Transitional Urbanism: planning for sustainable post-disaster recovery under uncertainty

Temporary Houses are often built by national governments and non-governmental organizations after disasters, for housing the homeless population until the end of reconstruction works. Nevertheless, Temporary Housing (TH) sometimes becomes a liability rather than an asset for the assisted communities, due to its ungoverned impact on transitional urbanism and on the long-term disaster recovery trajectory, including urban development. To achieve Building Back Better (BBB) goals and reduce future disaster risk, ensuring the sustainability of post-disaster housing assistance solutions is critical. To this end, prompt and longsighted planning is needed prior and during the construction of TH sites. Urban modelling and data analysis pipelines for scenario-based assessments could, in principle, be used to guide TH planning decisions, especially when traditional methods are likely to fail, due to the condition of uncertainty in which humanitarian actors operate. However, a truly evidence-based TH planning and design is hard to achieve as research in the field has not yet reached full maturity, and flexible planning tools, which tackle the complexity and variability of each disaster context as well as the lack of time and accessible information resources, are not currently available. Against this background, the thesis presents an analysis of progress, contradictions, and contentions in the field of post-disaster TH. It illustrates the historical experiences of Italy with recovery from earthquakes, considering how emergency management policies have evolved in response to different events and public debates, and highlights the main issues and gaps in quality and audit of the decision-making process which guided the TH provision in Central Italy in 2016-2017. Knowledge required to deliver a better and temporal TH assistance post-disaster is identified and multi-platform digital information packages and workflows for the comparative assessment of TH plans at different spatial scales are then developed. To this end, a systematic review of the state of the art on decision-making dichotomies and challenges in post-disaster housing assistance provision was first carried out. This prompted a set of applied tests and empirical elaborations in a selection of relevant case studies, which used a blend of quantitative and qualitative information, to identify the key processes, decision points and physical factors affecting the impact of TH plans on urban accessibility, liveability, and physical resilience. Formal information packages from digital tools, mostly rapid and collaborative, were integrated within adaptable and replicable analysis pipelines to better inform experts’ choices and increase their accountability. Multidimensional parametric urban models were adopted in the proposal to enable an integrated information management, considerate of cross-scale urban spatial dynamics. The themes cover change in urban form and transitional urbanism, as well as their relationship with sustainable disaster recovery, and include: (i) decision-making and TH strategic planning; (ii) urban and territorial post-disaster digital documentation and modelling; (iii) rapid geo-computation and collaborative digital workflows for TH assessment. The findings of this thesis bear some important implications for sustainable post-disaster recovery planning and contribute to advance Disaster Risk Reduction policies in line with the New Urban Agenda. Although from this study it remains uncertain how strategic planning influences sustainable urban development after disasters, the alignment of decisions taken at different governance levels, i.e., between strategic, managerial, and operational choices, was found to be crucial to achieve BBB. Taking the complexity of each context (including its regulatory framework) fully into account within a fit-for-purpose decision support system, was found critical for pursuing this decision-making alignment. Thus, the thesis advocates a holistic and human-centric approach to decision-making, which requires considerations of people’s needs and views as well as cities’ heritage. Adopting a configurational analysis approach proved useful to comparatively assess TH plans and to inform regenerative urban design interventions as the predicted socio-spatial performance of transitional settlements matched documentary evidence and reported facts in a satisfactory way. Results indicate the importance of TH sites’ morphology and urban configuration in restoring cities and the role of network analysis to assess that impact