Breakwater tetrapods
Tetrapods are a type of structure in coastal engineering used to prevent erosion caused by weather and longshore drift, primarily to enforce coastal structures such as seawalls and breakwaters. Tetrapods are made of concrete, and use a tetrahedral shape to dissipate the force of incoming waves by allowing water to flow around rather than against them, and to reduce displacement by interlocking.
Source Wikipedia
Photo gallery
Stability Formula for Tetrapods
A stability formula has been developed for Tetrapods armoring rubble mound breakwaters based on hydraulic model test results of the present and previous studies. The formula is applicable to breakwaters with various slope angles. It is also applicable to low-crested breakwaters and different packing densities if the corresponding terms are incorporated in the formula. The uncertainty of the formula is also described.
Stability Formula for Tetrapods
Other pdf documents:
Placement effect on the stability of tetrapod armor unit on breakwaters in irregular waves
Comparison of the Effect of Tetrapod Block and Armor X block on Reducing Wave Overtopping in Breakwaters