1. Department of Civil Engineering, North Carolina State University, Raleigh, NC 27695 e-mail:
2. Professor Department of Civil Engineering, North Carolina State University, Raleigh, NC 27695 e-mail:
3. Professor Department of Civil Engineering, Kyung Hee University, Yongin 17104, Gyeonggi-do, South Korea; Department of Civil Engineering, North Carolina State University, Raleigh, NC 27695 e-mail: