1. Department of Civil Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, Republic of Korea
2. Department of Civil and Environmental Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea
3. Department of Civil and Environmental Engineering, Hannam University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, Republic of Korea