1. Department of Civil Engineering, Xiamen University, Xiamen 361005, P. R. China
2. Xiamen Engineering Technology Center for Intelligent Maintenance of Infrastructures, Xiamen 361005, P. R. China
3. Department of Civil Engineering, Hefei University of Technology, Hefei 230009, P. R. China
4. Anhui Engineering Laboratory for Infrastructural Safety Inspection and Monitoring, Hefei University of Technology, Hefei, Anhui Province, P. R. China