1. Aerodrome Engineer (Design and Standards), Civil Aviation Authority of Sri Lanka, No. 4, Hunupitiya Rd., Colombo 2, Sri Lanka.
2. Professor, Dept. of Civil Engineering, Schulich School of Engineering, Univ. of Calgary, Calgary, Alberta, Canada T2N 1N4 (corresponding author).
3. Professor, Dept. of Civil Engineering, Schulich School of Engineering, Univ. of Calgary, Calgary, Alberta, Canada T2N 1N4.