1. CONSTRUCT-GEO, Faculty of Engineering (FEUP), Univ. of Porto, Rua Dr. Roberto Frias, s/n 4200-465 Porto, PT (Corresponding author), e-mail: smarisacsoares@gmail.com
2. CONSTRUCT-GEO, Faculty of Engineering (FEUP), Univ. of Porto, Rua Dr. Roberto Frias, s/n 4200-465 Porto, PT, e-mail: viana@fe.up.pt