1. Professor, Dept. of Civil Engineering, National Cheng Kung Univ., Tainan 70101, Taiwan.
2. Engineer, RAITO Engineering Corp., Kuan Chien Rd., 9th floor, Taipei, Taiwan; formerly, Graduate Student, Dept. of Civil Engineering, National Cheng Kung Univ., No. 1, Ta-Hseih Rd., Tainan, Taiwan.
3. Graduate Student, Dept. of Civil Engineering, National Cheng Kung Univ., No. 1, Ta-Hseih Rd., Tainan, Taiwan.