1. Associate Technical Specialist, Taiping District Office, No. 144, Zhongping Rd., Taiping District, Taichung City 411, Taiwan; formerly, Graduate Student, Dept. of Civil Engineering, National Chung Hsing Univ., Taichung 40227, Taiwan.
2. Associate Professor, Dept. of Civil Engineering, National Chung Hsing Univ., Taichung 40227, Taiwan (corresponding author).