Comprehensive design guidelines and literature on wave impacts at stepped revetments are lacking. Laboratory experiments are essential for establishing design recommendations, yet prior small-scale studies are likely to be subjected to scale effects. This study quantifies scale effects of wave impact characteristics by conducting full-scale flume experiments with two step heights. Results show that small-scale tests underestimate design wave impacts up to a factor of 7.7. Impact loadings occur considerably faster at full scale, with peak rising times decreasing by up to 5.6 times. Prediction formulae are dervied for the vertical distribution of maximum horizontal impact pressures as well as for temporal characteristics of these pressures at stepped revetments.
