1. School of Civil Engineering and Geomatics, Shandong Univ. of Technology, 266 Xincun West Rd., Zibo 255049, China; Longkou Housing and Urban-Rural Construction Administration Bureau, Yantai 265700, China.
2. Associate Professor, School of Civil Engineering and Geomatics, Shandong Univ. of Technology, 266 Xincun West Rd., Zibo 255049, China (corresponding author).
3. School of Civil Engineering and Geomatics, Shandong Univ. of Technology, Zibo 255049, China.