1. Scientist, Central Building Research Institute, Roorkee, 247 667 India. E-mail: mahamaha2001@yahoo.com
2. Scientist, Central Building Research Institute, Roorkee, 247 667 India. E-mail: vvgst@yahoo.com
3. Professor, Dept. of Civil Engineering, Indian Institute of Technology, Madras, Chennai, 600 036 India. E-mail: gopalkr@iitm.ac.in