1. Dept. of Civil Engineering, Curtin Univ. of Technology, GPO Box U1987, Perth 6845, Western Australia, Australia (corresponding author). E-mail: H.Nikraz@curtin.edu.au
2. Dept. of Civil Engineering, Curtin Univ. of Technology, GPO Box, U1987, Perth 6845, Western Australia, Australia.
3. Alcoa World Alumina Australia, PO Box 161, Kwinana 6966, Western Australia, Australia.