1. Professor, Dept. of Civil Engineering, Laval Univ., Quebec, Canada G1K 7P4.
2. Professor, Dept. of Applied Science, Univ. du Québec à Chicoutimi, Chicoutimi, Canada G7H 2B1.
3. Research Engineer, VSL International Ltd., Scheibenstrasse 70, 3014 Bern, Switzerland.