1. Post-Doctoral Researcher, Dept. of Civil and Environmental Engineering, Univ. of Maryland, College Park, MD 20742.formerly, Graduate Student, Dept. of Civil Engineering, Chulalongkorn Univ., Bangkok 10330, Thailand.
2. Professor, Dept. of Civil Engineering, Chulalongkorn Univ., Bangkok 10330, Thailand.
3. Professor Emeritus, Dept. of Civil and Environmental Engineering, Univ. of Maryland, 4201 Woodberry St., University Park, MD 20782.E-mail: