The Cost of Neglect

Abstract

Driven by climate change, the increasing frequency and intensity of flood events impose growing risks on urban infrastructure. To quantify these projected risks, conventional flood risk assessments rely on generic, univariate depth-damage curves that assume a pristine building stock. As a result, these methods systemically underestimate the vulnerability of historic unreinforced masonry dwellings that exhibit pre-existing structural degradation, exposing a critical scale gap between mesoscale risk modelling and microscale structural engineering physics. To bridge this gap, this thesis develops a multivariate, state-dependent probabilistic vulnerability framework that integrates component-level structural capacities with sociotechnical recovery timelines. The framework is applied to two residential case study locations, which reveals that initial degradation shifts damage onset to lower flood depths. Mean repair costs yield a 5 to 8 percentage point divergence in median repair costs. Crucially, crossing into extensive structural damage triggers compounding procurement and permitting delays that severely elevate re-occupancy downtime, extending community displacement from two months to over a year. While component adaptation mitigates direct interior losses, preflood structural restoration is more effective in reducing median re-occupancy downtime by up to 40.7%. This framework establishes a scalable tool to improve current flood risk assessments and enable targeted climate adaptation and heritage preservation investments within ageing urban environments.