1. a School of Civil Engineering , University of Technology , Sydney , PO Box 123 Broadway, NSW, 2007, Australia
2. b Department of Civil Engineering , Oregon State University , Apperson Hall 202, Corvalis , Oregon , 97331.2302 , U.S.A.
3. c Lahoratoire Méthodes, Génie Civil & Urbanisme , INSA de Lyon , 20, avenue Albert Einstein, Bat. 304, F69621 , Villeurbanne Cedex