1. Associate Professor, Dept. of Civil Engineering, National Taiwan Univ., No. 188, Sec. 3, Sinhai Rd., Taipei, 106, Taiwan (corresponding author).
2. Ph.D. Student, School of Civil Engineering, Purdue Univ., 550 Stadium Mall Dr., West Lafayette, IN 47906.
3. Deputy Administrator, Industrial Technology Research Institute, 195, Sec. 4, Chung Hsing Rd., Chutung, Hsinchu, Taiwan 31040.
4. Professor, Hydrotech Research Institute, National Taiwan Univ., No. 158, Chowshan Rd., Taipei, 106, Taiwan.
5. Professor, Hydrotech Research Institute, NTU, No. 158, Chowshan Rd., Taipei, 106, Taiwan.