Abstract
Encroachment of infrastructure on the natural beach system constrains dune volumes and necessitates construction of structural and nonstructural mitigation measures to improve coastal resilience. Nature-based solutions, such as dunes reinforced with geosynthetic sand containers (GSCs), are increasingly being used to stabilize coastlines and protect communities from smaller storm events (e.g. 50-year storms) while at the same time providing flexibility in design considering the uncertainty regarding rates of sea level rise and the increasing destructive power of storm events. Using risk-based hazard assessments, such as fragility curves, it is possible to quantify the resiliency of reinforced coastal systems to address these dynamic conditions. A fragility curve represents the conditional probability of failure of a coastal structure (e.g. natural dune, reinforced dune, seawall, etc.) as a function of a certain stress acting on the structure (typically water level, wave height/period; Gruhn et al. 2012). The main advantage of a fragility curve, compared to a damage function that quantifies a deterministic degree of damage directly to a stress, is that it can account for uncertainties in both the structural resistance (i.e. capacity) and the environmental stress (i.e. demand) of the system. The objective of this research is to present a fragility analysis of a U.S. Federally funded GSC-reinforced dune in Montauk, NY. This dune was constructed in 2016 and experienced significant erosion of the protective berm and sand covering the GSCs during a 1-year storm event that same year.References
Gruhn, Salecker, Fröhle, Schüttrumpf, and Thorenz (2012): Flood Protection Dunes – An Approach for Reliability Assessment by Means of Fragility Curves as Part of a Risk and Damage Analysis, Proceedings of 33rd International Conference on Coastal Engineering.
Oumeraci, Hinz, Bleck, and Kortenhaus (2003): Sand-filled Geotextile Containers for Shore Protection. Coastal Structures 2003, 1-15.
USACE (2007): Shore Protection Assessment – How Beach Nourishment Projects Work. U.S. Army Corps of Engineers, Coastal and Hydraulics Laboratory, Engineer Research and Development Center.
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