1. Hokkaido Bureau, Ministry of Land, Infrastructure and Transport , Kasumigaseki 2-1-3, Chiyoda-ku, Tokyo 100-8918, Japan
2. Otaru Port Construction Office, Hokkaido Development Bureau , Chikko 2–2, Otaru, 047-0008, Japan
3. Port and Harbor Engineering Division, Civil Engineering Research Institute of Hokkaido , Hiragishi 1–3, Toyohira, Sapporo 062-8602, Japan
4. Maeda Corporation , Takamatsu 5–8, Nerima-ku, Tokyo 179-8903, Japan