1. Assistant Professor, Dept. of Civil Engineering, Suzhou Univ. of Science and Technology, Jiangsu 215011, China; Former Researcher, Dept. of Civil and Earth Resources Engineering, Kyoto Univ., Kyoto 606-8501, Japan (corresponding author).
2. Assistant Professor, Dept. of Civil and Earth Resources Engineering, Kyoto Univ., Kyoto 606-8501, Japan.
3. Associate Professor, Dept. of Civil Engineering, Kobe Univ., Kobe 657-0013, Japan.
4. Professor, Dept. of Civil and Earth Resources Engineering, Kyoto Univ., Kyoto, 606-8501, Japan.