1. Ph.D. Candidate, Dept. of Civil and Environmental Engineering, Ehime Univ., Matsuyama 790-8577, Japan (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, Ehime Univ., Matsuyama 790-8577, Japan.
3. Assistant Professor, Dept. of Civil Engineering and Architecture, Tokuyama College of Technology, Shunan 745-8585, Japan.
4. Assistant Professor, Dept. of Civil and Environmental Engineering, Ehime Univ., Matsuyama 790-8577, Japan.
5. Professor, Dept. of Civil Engineering, Univ. of Peradeniya, Peradeniya 20400, Sri Lanka.