Masahiro Ito, Yuichi Iwagaki, Hiroshi Murakami, Kenji Nemoto, Masato Yamamoto, Minoru Hanzawa


The stability coefficient of the well-known the Hudson formula, KD, has been established by many laboratory tests for various types of armor blocks with a range of specific gravity 2.16-2.47 representative of normal concrete. Design manuals for coastal structures do not describe the adoption of high-specific gravity armor blocks for use in field construction. To examine the effect of specific gravity on stability of Tetrapods, then a laboratory test was conducted by using Tetrapod models of different weights which are composed of five values of specific gravities. Temporal changes of damage ratio arranged test conditions that satisfy the Hudson formula do not coincide among each other, depending on wave period and specific gravity. The effect of the specific gravity on their stability is discussed. As a result, it is found that the relationship between the stability and the specific gravity is considerably affected by the surf similarity parameter and Reynolds number.


armor; armor blocks; armor stability

Full Text: PDF

Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.