1. Assistant Professor, Dept. of Architectural Engineering, Mokpo National Univ., 61 Dorim-ri, Cheongggye-myeon Muan-gun, Jeonnam 534-729, South Korea.
2. Principal Researcher, Daewoo Institute of Construction Technology, Daewoo E&C Co., Ltd., 60 Songjuk-dong Jangan-gu, Suwon 440-210, South Korea (corresponding author).