1. Assistant Professor, Dept. of Civil Engineering, Univ. of Suwon, 445-743, Wauan-gil 17, Bongdam-eup, Hwaseong-si, Gyeonggi-do, South Korea; formerly, Research Assistant Professor, Dept. of Civil Engineering and Engineering Mechanics, Univ. of Arizona, Tucson, AZ 85721 (corresponding author).
2. Professor, Dept. of Civil Engineering and Engineering Mechanics, Univ. of Arizona, Tucson, AZ 85721.