1. Department of Civil and Building Engineering, Loughborough
University, Loughborough, LE11 3TU, UK
2. CERA Institute, Unigraphics Solutions, P.O. Box 3882,
Tustin, CA 92781-3882 USA
3. Universite de Savoie-ESIGEC/LGCH, Domaine de Savoie-Technolac,
73376 le Bourget du Lac, France