1. Grad. Student, Dept. of Civ. Engrg., Nagoya Univ., Chikusa-ku, Nagoya 464-01, Japan.
2. Asst. Prof., Dept. of Civ. Engrg., Nagoya Univ., Chikusa-ku, Nagoya 464-01, Japan.
3. Prof., Ctr. Integrated Res. in Sci. and Engrg., Nagoya Univ., Chikusa-ku, Nagoya 464-01, Japan.