1. Research Assistant, Dept. of Civil Engineering, Univ. of Peradeniya, Peradeniya 20400, Sri Lanka (corresponding author).
2. Professor, Dept. of Civil Engineering, Univ. of Peradeniya, Peradeniya 20400, Sri Lanka. E-mail: sbweera@ pdn.ac.lk
3. Senior Academic Programme Officer, United Nations Univ., Institute of Sustainability and Peace, UNU Center, 53–70, Jingumae 5-chome, Shibuya-ku, Tokyo 150-8925, Japan.