1. Sr. Lect., Dept. of Civ. Engrg., Nair Service Society Coll. of Engrg., Palakkad 678 008, India (corresponding author). E-mail: ckpvarma@yahoo.com
2. Deceased Dec. 10, 2000; formerly, Prof., Struct. Engrg. Div., Dept. of Civ. Engrg., Indian Inst. of Technol. Madras, Chennai 600 036, India.