Wave-in-deck loads on exposed jetties

Abstract

This paper presents results from research on the hydraulic loadings of exposed (unsheltered) jetties (open pile piers with decks and beams). The work presented here focuses on results from physical model tests on wave-induced loads on deck and beam elements of exposed jetties and similar structures. These tests investigated the physics of the loading process, and provided new guidance on wave-in-deck loads to be used in design. Wave forces and pressures were measured on a 1:25 scale model of a jetty head with projecting elements. Structure geometry and wave conditions tested were selected after an extensive literature review (summarised in the paper) and consultation with the project steering group. Different configurations were tested to separate 2-d and 3-d effects, and to identify the effects of inundation and of down-standing beams. Results presented in this paper have been obtained by re-analysing wave loads using wavelet analysis to remove corruption from the dynamic responses of the instrumentation. Both quasi-static and impulsive components of the loading were identified. Previous methods to predict wave loading on jetty elements (decks and beams) were tested against these new data and clear inconsistencies and gaps were recognised. New dimensionless equations have been produced to evaluate wave forces on deck and beam elements of suspended deck structures. The results are consistent with the physics of the loading process and reduce uncertainties in previous predictions.