1. Professor, Dept. of Civil and Construction Engineering, National Taiwan Univ. of Science and Technology, #43, Section 4, Keelung Rd., Daan District, Taipei 8862, Taiwan.
2. Researcher and Lecturer, Institute of Research and Development, Duy Tan Univ., P809—K7/25 Quang Trung, Danang 550000, Vietnam (corresponding author).