Large-scale experiments were earried out to investigate impact forces on cylinders due to breaking waves. Wave breaking was induced by converging wave packets. The wave kinematics, the impact and the response of the cylindrical structure were measured simultaneously. The slender test cylinder was installed vertical and inclined towards and against wave direction. Values of the actual impact force are determined and compared for the different angles of inclination.
Loads acting on a slender vertical cylinder attacked by a breaking wave were investigated first (Wienke et al., 2000). The total force was separated into a quasistatic and a dynamic force. The quasistatic force is described by the Morison equation and the dynamic force is related to the impact of the breaking wave. This impact was successfully analysed by deconvoluting the measured force. It was found that the description of Wagner (1932) is in good agreement with the 2–1:) impact force. The transition to the 3-D impact force was achieved by inserting the curling factor. The evaluation method was transferred to the tests with the inclined cylinder. In this way a better understanding of the time history of the impact on a cylindrical structure was developed. Moreover the range of application for the description of the impact was enlarged. To date breaking wave impact on inclined cylinders was only investigated by Tanimoto et al. (1986). Tanimoto et al. found that the impact force increases greatly as the cylinder is inclined seaward and the impact force decreases as the cylinder is inclined shoreward. EXPER/MENTAL SET-UP The experiments were carried out in the LARGE WAVE CHANNEL of the FORSCHUNGSZENTRUM KOSTE (Coastal Research Centre) in Hannover, Germany. This channel has a length of 309 m, a width of 5 m and a depth of 7 m.
