Use of Numerical and Statistical Wave Models in the Structural Design and Operational Analysis of Harbor and Near-shore Structures

Abstract

Numeric and statistical wave models allow the waterfront engineer to quickly and accurately evaluate site specific wave conditions. Infrequent return period storms typically govern the wave criteria for structural design. However, day to day wave climate may have a significant impact on the operation of a facility. This paper will examine the wave statistics utilized to determine both maximum and daily design wave conditions. As wave or wind data are not always available on a site specific basis, the paper will also discuss use of numerical wave models to transfer the wave data to the site of interest. Available sources of wind and wave data are discussed. The available data must be analyzed and converted to the appropriate statistical value for the required analysis. For infrequent storm conditions, a “peaks over threshold” analysis method is utilized to determine return period wave or wind conditions. Daily operational conditions are determined utilizing a joint probability distribution for a finite number of direction/wind speed or direction/wave period and wave height/period bins. Once the design wind and wave statistics are calculated, the numeric wave models are utilized to transfer the waves to site. Examples of use of the described methodology are provided including: design of a mooring system for container barge; design of a near-shore mooring system for aquaculture applications; and site evaluation for nearshore wave to energy facilities.