Stability of breakwater armor units against tsunami attacks

The design of breakwater armor units against tsunami attacks has received little attention in the past because of the comparative low frequency of these events and the rarity of structures designed specifically to withstand them. However, field surveys of recent events, such as the 2011 Tohoku Earthquake Tsunami and the Indian Ocean tsunami in 2004, have shown flaws in the design of protection structures. During these extreme events, many breakwaters suffered partial or catastrophic damage. Although it is to be expected that most normal structures fail because of such high-order events, practicing engineers need to possess tools to design certain important breakwaters that should not fail even during Level 2 events. In the future, research into the design of critical structures that only partially fail (i.e., resilient or tenacious structures) during very extreme Level 2 tsunami events should be a priority; in this sense, the present paper proposes a formula that allows the estimation of armor unit damage depending on the tsunami wave height.