1. Dept. of Construction Engineering, Chaoyang Univ. of Technology, 168, Jifeng E. Rd., Wufeng District, Taichung City 41349, TW (Corresponding author), e-mail: phtsai@cyut.edu.tw
2. Dept. of Soil and Water Conservation, National Chung Hsing Univ., 145 Xingda Rd., South Dist. Taichung City 40227, TW, e-mail: tonyfeng@nchu.edu.tw
3. Dept. of Civil Engineering, National Cheng Kung Univ., No.1, University Road Tainan City 70407, TW, e-mail: tonyni@mail.ncku.edu.tw