1. Formerly, Graduate Student, Dept. of Civil Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
2. Professor, Dept. of Civil Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India (corresponding author).
3. Professor, Dept. of Civil and Resource Engineering, Dalhousie Univ., Halifax, NS, Canada B3H 4R2.