1. INESC Coimbra; Rua Antero de Quental 199; 3000-033 Coimbra Portugal
2. Civil Eng. Dept.; University of Coimbra; Rua Luís Reis Santos 3030-788 Coimbra Portugal
3. ICIST; 1049-001 Lisboa Portugal
4. Civil Eng. Dept.; Instituto Superior Técnico; Av. Rovisco Pais 1049-001 Lisboa Portugal
5. Dept. of Civil Engineering and Geosciences; Delft University of Technology; P.O. Box 5048 2600 GA Delft The Netherlands
6. Physics Dept.; University of Évora, Colégio Luís António Verney; Rua Romão Ramalho 59 7002-554 Évora Portugal