1. Research Scholar, Dept. of Civil Engineering, Indian Institute of Technology, Kharagpur 721 302, India.
2. Associate Professor, Dept. of Civil Engineering, Indian Institute of Technology, Kharagpur 721 302, India.
3. Professor, Dept. of Civil Engineering and Geodesy, Darmstadt Univ. of Technology, Petersenstraße 30, 64287 Darmstadt, Germany.