Dissipation Effects of Coastal Vegetation on Nearshore Structures under Wave Runup Loading

摘要

Inundation events caused by hurricanes or tsunamis pose a substantial risk to the integrity of coastal infrastructure; however, their impact on the built environment can be greatly altered by natural and anthropogenic obstacles or disturbances to the flow, such as vegetation or neighboring structures. This paper investigates the impact of coastal vegetation on shoreline structural vulnerability due to wave runup loading. Using numerical simulation data, the load (base shear) and momentum flux are computed as a function of vegetation characteristics (length and density) for different excitation intensities (wave heights) at the location of a shoreline structure. This information is then used to estimate structural fragility. Motivated by recent reconnaissance data from Hurricane Matthew in 2016, emphasis is placed on the out-of-plane failure of infill masonry walls. Extension to a different structural typology, that of a reinforced concrete frame, is also discussed. Comparisons between different vegetation characteristics and the bare-earth case demonstrate the wave dissipation and reduction of structural fragility (and therefore ultimately vulnerability) achieved when vegetation is present for the investigated case-study structures. (C) 2020 American Society of Civil Engineers.