Performance of Coastal Structures against Sequences of Hurricanes

Abstract

A synthesis of existing models and formulas is made to compute the virtual performance of rubble mound structures in shallow water under combined storm surge and breaking waves for sequences of hurricanes. The computed results for ten 500-year simulations are presented for a typical structure as an example. The crest height and armor weight of the structure are designed against the peak of a 100-year storm. The structure designed conventionally is exposed to approximately 350 storms for each 500-year simulation. The computed wave overtopping rate and volume during the entire duration of each storm are analyzed to assess the severity of flooding hazards. The computed progression of damage to the armor layer is caused episodically by several major storms but slows down as the structure ages. The computed results are also used to quantify the equivalent duration of the peak of a storm that yields the same overtopping water volume and damage increment as those computed for the entire storm duration.