From Structural Damage Assessment to Functionality Estimation: A Comprehensive Modeling Approach for Buildings Subjected to Hurricane Winds
Advisor: Associate Professor Eun Jeong Cha
Abstract
Buildings are critical to the built environment and human daily lives, providing essential functions such as housing, healthcare, education, retail, manufacturing, etc. The occurrence of natural hazards can compromise buildings structurally and functionally. Building structural damage can cause immediate consequences such as injury and death, while building functionality loss can cause extensive socio-economic disruptions, such as population dislocation and business shutdown.
As one of the most devastating natural hazards in the United States, hurricanes pose significant risk to buildings of all types, not only causing physical damage but also disrupting their functionality. Despite the clear impact on building functionality, research on estimating the functionality loss of buildings subjected to hurricanes has been limited. Existing research on building functionality under hurricanes has primarily focused on structural damage, neglecting the significant impact of nonstructural systems on building functionality. This dissertation addressed this gap by developing a comprehensive model that estimates the functionality of buildings subjected to hurricane winds, considering both structural and nonstructural systems at a component-level resolution. The impact of hurricane wind, wind-borne debris, and wind-driven rain was considered in this model.
As the foundation of building functionality, an accurate estimation of building structural damage is crucial for an accurate building functionality estimation. A comprehensive review of the existing building structural damage simulation models conducted by this research revealed large variability in the building structural damage estimation. To reduce this variability, this research proposed a data-informed simulation model development approach. In this approach, the model parameters of the simulation models are calibrated using the post-hurricane building damage data collected from historical hurricane events. A data-informed simulation model was then developed for a specific building class (one-story, gable roof, non-elevated, year built<2001 wood-frame residential buildings) to demonstrate this approach. The performance of the developed model was validated against real-world building damage data and compared to the performance of existing simulation models. The results showed that using the data-informed simulation model significantly improved the accuracy of structural damage prediction compared to using existing simulation models.
The damage to the nonstructural building systems (interior, electrical, HVAC systems) were also explicitly modeled in this research. Two types of damage mechanisms were incorporated: rainwater-induced damage and component dependency-induced damage. To accurately simulate the damage of building internal systems, the water intrusion and propagation paths inside the building were modeled in detail and the amount of rain ingress was calculated at a room-level resolution. Furthermore, network analysis was employed to capture the complex dependency relationships between building components of various building systems. The application of network analysis offers an accurate estimation of the functionality loss of the inside-the-building utility systems (electrical and HVAC systems).
The functionality of the entire building was then estimated by incorporating the damage to the building structural and nonstructural systems. The proposed building functionality estimation
model was applied to estimate the functionality of the shelter function for a wood-frame residential building. Fragility curves for the functionality states of individual building systems as well as the entire building were developed and analyzed. The analysis highlighted the significant role of nonstructural building systems in supporting the building functionality, revealing that considering the building structural system only will significantly underestimate the building functionality loss under hurricanes.