1. School of Civil Engineering, Central South University, Changsha, P.R. China
2. Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO, USA
3. School of Civil Engineering, Changsha University of Science and Technology, Changsha, P.R. China
4. Guizhou Transportation Planning Survey and Design Academe Co., Ltd., Guiyang, P.R. China
5. Yingyun Highway Administration Bureau of Guizhou Province, Guiyang, P.R. China