An experimental study aiming to measure wave-induced forces on key elements of exposed jetties has been carried out by a combined research team. The experimental set-up was designed to measure wave loading, both horizontal and vertical, on external (seaward) and internal (middle of deck) elements of a model of a jetty head. Pulsating and impulsive loads are analysed in dimensionless form, and differences between three different structure configurations are described.
Wave loading on maritime structures has been studied in the past 40 years, but nearly always involves significant simplifications of the wave / structure interaction. The characteristics of wave forces on coastal structures depend strongly on their location with respect to wave shoaling and breaking. Offshore structures (like oil platforms) are generally subject to non-breaking waves where most wave loads may be termed "pulsating". Nearshore or coastal structures like jetties may however be placed in shallow water where waves are breaking or already broken. Some wave loads may therefore be more violent, especially on vertical walls, see e.g. Allsop (2000). In the last 10–15 years, increasing demand for longer jetties to provide large vessels mooring has required the construction of these structures in significantly deeper water. ‘Exposed jetties’ extend therefore from shallow to deep water, and the dynamic of wave-induced loading is influenced from the transition. This paper is focused to interpret results of an experimental study of wave-induced forces on a model of a jetty located in transitional water. General characteristics of wave-induced forces on maritime structures are described and a literature review of methods used to measure and/or evaluate them is presented. New experimental data collected at HR Wallingford are then analysed in a dimensionless form, to provide some guidance on the magnitude of pulsating and impulsive forces applied to deck and projecting elements of jetties.