1. Professor, Civil Engineering Dept., Univ. of Shanghai, No. 99, Shangda Road, Shanghai 200444, China (corresponding author).
2. Master Student, Civil Engineering Dept., Univ. of Shanghai, No. 99, Shangda Road, Shanghai 200444, China.
3. Master Student, Civil Engineering Dept., Univ. of Shanghai, No. 99, Shangda Road, Shanghai 200444 China.
4. Professor, Institute of Applied Mathematics and Mechanics, Univ. of Shanghai, No.149, Yanchang Road, Shanghai 200072, China.