1. Professor, Dept. of Civil Engineering, National Taipei Univ. of Technology, NTUT Box 2653, No. 1, Section 3, Jungshiau East Rd., Taipei 10608, Taiwan, Republic of China (corresponding author).
2. Ph.D. Candidate, National Taipei Institute of Technology, National Taipei Univ. of Technology, No. 1, Section 3, Zhongxiao E Rd., Da’an District, Taipei City, Taipei 10608, Taiwan, Republic of China.