This multi-disciplinary NSF sponsored research project develops a framework to support the conceptual design of resilient and sustainable building systems (RSB) by providing robust estimates of building resiliency and sustainability over a broad set of soil, foundation, structural, and envelope (SFSE) systems.
PI: Madeleine Flint (College of Engineering)
The research framework includes consideration of the full spectrum of possible events as well as interdependent hazard and performance, allowing the identification of optimal candidates systems while minimizing the data and analysis required of the design engineer. The project scope includes: development of the framework and methodologies for incorporating hazards and SFSE systems for a particular building type; generation of appropriate models and datasets for midrise office buildings under hurricane, earthquake, and tsunami hazards; sensitivity studies of the effect of aleatoric and epistemic uncertainty in hazard, performance, and metrics; and application of the framework to a case study structure located in Charleston, South Carolina.
The RSB multi-hazard framework assesses SFSE systems in three modular phases: (1) generation of SFSE alternatives appropriate for the considered site using a rating method that identifies applicable systems and their subsystem interdependencies; (2) probabilistic multi-hazard resiliency and sustainability performance assessment based on hazard, fragility, and loss curves adapted to reflect interdependencies and quality; and (3) multi-objective and multi-criteria optimization of performance metrics associated with system alternatives to identify candidate systems. By considering a broad design space, the framework supports the selection of SFSE systems that meet user constraints, are equally optimal across the sustainability metrics, and are aligned with user preferences. Feedback loops maintain flexibility of use, as decision-makers may iteratively adapt preferences and constraints or incorporate building-specific hazard and fragility data.
Hurricane, earthquake, and tsunami hazards are researched due to their large social, economic, and environmental impacts, as well as their contribution of unique challenges to the development of the RSB framework. Hurricanes are associated with interdependent multi-hazard components, including storm surge, wind, and rain, while the pairing of earthquake and tsunamis reflects cascading hazard and performance interdependencies. All considered hazards may have a significant impact on post-recovery building operation, supporting the identification of further interdependent performance aspects. Some locations in the US experience these hazards in combination, e.g. Charleston, S.C., which makes these hazards an important testbed in identifying the tradeoffs between multi-hazard resiliency and life-cycle sustainability.
The performance metrics link resiliency to sustainability as follows: economic impact is associated with the life-cycle cost of the building, including losses due to natural hazard related to building robustness; social impact is considered by focusing on the rapidity dimension of resilience, or the time for the building and its occupants to return to normalcy; environmental impact is considered by measuring the Greenhouse Gas emissions and the energy consumption of buildings over their construction and operation life-cycle, including the contributions of natural hazards (robustness).
Midrise commercial office buildings are highly engineered, prevalent across the United States, consume a significant portion of US commercial building energy consumption, and are essential to communities’ economic and governmental functions. SFSE systems used in office buildings of 3-5 stories were therefore selected as an ideal building type for the framework development. Numerous combinations of soil (ground-improvement), foundation (shallow and deep), structural (moment walls, shear walls, braced frames, light-framed), and envelope (drained wall, barrier wall, flat and pitched roofs) subsystems are studied.