Storm Surge and Wave Loading on Horizontal Superstructures

Until recently, few methods existed in the literature for the application of wave loading on horizontal superstructures located in coastal regions. In fact, the U.S. Army Corps of Engineers Coastal Engineering Manual, or CEM (the industry standard for coastal construction), contains no methodologies for calculating loads on horizontal superstructures. Although significant effort has been devoted to the development of predictive equations for wave loads on vertical structures such as piles and seawalls, predictive equations for horizontal superstructures have been limited to offshore platforms in ocean wave conditions. Wave conditions in coastal waters can vary significantly from those in the ocean. Wave periods, and therefore wave lengths, in coastal waters are much shorter. Correspondingly, the ratio of the width of coastal superstructures to the wave length is much greater than those ratios encountered in the offshore environment. Thus, wave-induced water particle velocities and accelerations vary significantly over the width of the structure as compared with offshore structures. This results in corresponding variations in wave forces on the structure. Previous researchers presented a mathematical model applicable to structures in coastal environments. This paper reviews the development of that methodology and presents a case study as well as comparisons with other recently developed methodologies.