1. Res., Dr. of Engrg., Civ. and Envir. Engrg. Dept., Facu. of Engrg., Saitama Univ., 255 Shimo-okubo, Urawa-shi, Saitama 338-8570, Japan.
2. Asst. Mgr., Civ. and Arch. Engrg. Dept., Japan Nuclear Fuel Ltd., Fukokuseimei Build. 2-2-2, Uchisaiwai-cho, Chiyoda-ku, Tokyo 100-0011, Japan.
3. Prof., Civ. and Envir. Engrg. Dept., Facu. of Engrg., Saitama Univ., 255 Shimo-okubo, Urawa-shi, Saitama, Japan.