1. Postdoctoral Research Associate, Dept. of Civil and Structural Engineering, Univ. of Sheffield, Sir Frederick Mappin Bldg., Mappin St., Sheffield S1 3JD, U.K.; formerly, Research Fellow, Faculty of Engineering, Univ. of Nottingham, Nottingham NG7 2RD, U.K.
2. Research Officer, European Commission, Joint Research Centre (JRC), Institute for the Protection and Security of the Citizen (IPSC), European Laboratory for Structural Assessment, TP480, via Enrico Fermi 2749, I-21020 Ispra, Italy (corresponding author).