1. Dipartimento di Meccanica Strutturale, Istituto di Matematica Applicata e Tecnologie Informatiche, and European School for Advanced Studies in Reduction of Seismic Risk (ROSE School), Università degli Studi di Pavia, Via Ferrata 1, 27100 Pavia, Italy
2. Dipartimento di Meccanica Strutturale, and European School for Advanced Studies in Reduction of Seismic Risk (ROSE School), Università degli Studi di Pavia, Via Ferrata 1, 27100 Pavia, Italy
3. School of Civil and Environmental Engineering, Georgia Institute of Technology, 790 Atlantic Drive, Atlanta, GA 30332-0355