1. Associate Professor, Department of Civil and Environmental Engineering, The Bialystok Univ. of Technology, 15-351 Bialystok, Wiejska Street 45A, PL (Corresponding author), e-mail: kadamska@pb.edu.pl
2. Associate Professor, Department of Civil and Environmental Engineering, The Bialystok Univ. of Technology, 15-351 Bialystok, Wiejska Street 45A, PL, e-mail: m.sulewska@pb.edu.pl