1. Faculty of Engineering, Dept. of Quantity Surveying, Sri Lanka Institute of Information Technology, Malabe 00800, Sri Lanka.
2. Faculty of Engineering and Environment, Dept. of Architecture and Built Environment, Northumbria Univ., Newcastle Upon Tyne NE1 8ST, UK.
3. Faculty of Engineering and Environment, Dept. of Architecture and Built Environment, Northumbria Univ., Newcastle Upon Tyne NE1 8ST, UK (corresponding author).