1. School of Highway, Chang'an University, Middle Section of South Erhuan Road, Xi'an, Shaanxi 710064, CN (Corresponding author), e-mail: zhjiupeng@163.com
2. School of Highway, Chang'an Univ., Middle Section of South Erhuan Rd., Xi'an, Shaanxi 710064, CN, e-mail: biyanqiu@chd.edu.cn
3. Dept. of Civil and Environmental Engineering, Rutgers, The State Univ. of New Jersey, New Brunswick 08901, NJ, US, e-mail: hwang.cee@rutgers.edu
4. Shaanxi Provincial Expressway Construction Group CO., 9 South Taibei Rd., Xi'an, Shaanxi 710065, CN, e-mail: xinhongyang_sxgs@126.com
5. Tianjin Municipal Engineering Research Inst., 39 Pingshan Rd., Tianjin 300074, CN, e-mail: liushenglin0811@163.com