Collaborative Research: Modeling Hurricane-Induced Windborne Debris to Reduce Damage in Urban Communities

Colorado State University, Fort Collins CO

Investigators

Abstract

Numerous post-hurricane investigations have reported excessive and costly damage to glass cladding and façades of buildings located in urban areas. The resulting interior rainwater damage and extended periods of loss in building functionality can have substantial adverse effects on the socio-economic systems within and surrounding urban communities. Past studies of damage after high wind events have recognized that more than 80% of glass breakage was caused by windborne debris (such as broken glass pieces and materials from neighboring buildings) rather than direct wind pressure loading the glass. Appropriate cost-effective solutions begin with a comprehensive understanding of this vulnerability. However, the highly turbulent urban wind field around densely clustered buildings significantly complicates the accurate modeling and prediction of windborne debris transport and impact. This project will model the underlying physical process of the debris impact on clustered urban buildings through a combination of 1) a novel wind tunnel test program at the NSF-supported Natural Hazards Engineering Research Infrastructure (NHERI) boundary layer wind tunnel at the University of Florida, 2) data-driven computer simulation approaches, and 3) physics-based models of debris origin, flight, and impact. The result will be a new debris damage vulnerability assessment platform that enables risk-consistent efforts to reduce wind damage to the urban building envelope. Concurrent with the research, an interactive augmented reality tool will be developed to visualize the three-dimensional flow around building clusters and debris flight trajectory. This will be the centerpiece of a summer program that exposes high school students from underrepresented groups to engineering and encourages STEM career paths. Data generated by this project will be archived and made publicly available in the NHERI Data Depot (https://www.DesignSafe-ci.org). This research project will advance the understanding and modeling of the underlying physics of debris transport in urban winds through explicit modeling of complex urban flow features and debris flight trajectories around building clusters. This will directly address the current knowledge gap present in modeling of urban windborne debris hazard mechanisms. New wind tunnel experimental techniques will enable the project team to capture three-dimensional urban wind fields and debris trajectories, resulting in first-of-its-kind data necessary for developing the data-driven wind field models and systematically validating numerical trajectory models for complex urban winds. A novel integration between the wind tunnel experiments and data-driven modeling will be developed through active learning to efficiently predict wind fields for generic building clusters where wind tunnel data is not available. A probabilistic uncertainty quantification procedure will be developed to evaluate windborne debris damage risk through rigorous propagation of uncertainties from debris sources, urban wind fields, debris trajectory, and impact models. The outcome of this project will enable assessment and improvement of hurricane resilience for urban building clusters, which is a significant research gap present in community resilience planning. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.