1. Professor of Civil Engineering, JNTU College of Engineering, Kakinada 533 003 India.
2. Professor of Civil Engineering, Vellore Institute of Technology, Vellore 632 014, Tamilnadu, India. (corresponding author). E-mail: phanikumar_29@yahoo.com
3. Research Associate, Dept. of Civil Engineering, JNTU College of Engineering, Kakinada 533 003 India.