ICCE 2018 Cover Image

Supplementary Files

Conference Presentation File

How to Cite

Bekker, J., Hofland, B., & Smith, G. (2018). EXPERIMENTS ON THE EFFECT OF FREEBOARD ON THE STABILITY OF A BREAKWATER CROWN WALL. Coastal Engineering Proceedings, 1(36), papers.9. https://doi.org/10.9753/icce.v36.papers.9


A crown wall is a gravity based structure on top of a rubble mound breakwater which gains stability due to its own weight and friction between the base and contact surface of the rubble mound. An experimental research is carried out in which the global stability of a crown wall is investigated depending on, amongst other things, freeboard. Until now, these structures tend to be designed in a too conservative way, when the vertical distance between base slab and water level (base freeboard) increases. It was concluded that current design methods overpredict vertical loads for increasing freeboard. By implementing a reduction factor for the upward pressure acting on the base slab of the crown wall, a better prediction can be made for the transition region between stability and failure.


Berenguer, J. and Boanza, A. (2006) Rubble mound breakwater crown wall design. In Proceedings of the National Conference of the Port and Coastal Technical Association, Algeciras, Spain (in Spanish).

Bradbury, A. and Allsop, N. (1988) P5. Hydraulic effects of breakwater crown walls. In Design of breakwaters, Thomas Telford Publishing. 385-396

Braña and Guillén [2005] Wave forces on crown walls: evaluation of existing empirical formulations. In Coastal Engineering 2004: (In 4 Volumes),World Scientific. 4087-4099

Bruun, P. (2013) Design and construction of mounds for breakwaters and coastal protection, vol. 37. Elsevier

CIRIA, C. et al. (2007) The rock manual. CIRIA London

Gunbak, A. and Gökce, T. (1984) Wave screen stability of rubble-mound breakwaters. In International symposium of maritime structures in the Mediterranean Sea. Athens, Greece. 99-112

Martin, F.L., Losada, M.A. and Medina, R. (1999)Wave loads on rubble mound breakwater crown walls. Coastal Engineering, 37(2), 149-174

Negro Valdecantos, V., L´opez Gutiérrez, J.S. and Polvorinos Flors, J.I. (2013) Comparative study of breakwater crown wall-calculation methods. In Proceedings of the Institution of Civil Engineers-Maritime Engineering. Thomas Telford (ICE Publishing), vol. 166, 25-41

Nørgaard, J.Q.H., Andersen, T.L. and Burcharth, H.F. (2013) Wave loads on rubble mound breakwater crown walls in deep and shallow water wave conditions. Coastal Engineering, 80, 137-147

Pedersen, J. (1996) Wave forces and overtopping on crown walls of rubble mound breakwaters. Phd

Authors retain copyright and grant the Proceedings right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this Proceedings.