1. Assistant Professor, Dept. of Civil and Environmental Engineering, Saitama Univ., 255 Shimo-Okubo, Sakura-ku, Saitama-shi, Saitama-ken 338-8570, Japan.
2. Professor, Dept. of Civil and Environmental Engineering, Saitama Univ., 255 Shimo-Okubo, Sakura-ku, Saitama-shi, Saitama-ken 338-8570, Japan.
3. Engineer, Sumitomo Mitsui Construction Co., Ltd., Tokyo, Japan.
4. Engineering Researcher, Oriental Construction Co., Ltd., Tokyo, Japan.