1. Department of Engineering Mechanics, Vilnius Gediminas Technical University, Saulėtekio al. 11, LT-10223 Vilnius, Lithuania
2. Department of Bridges and Special Structures, Vilnius Gediminas Technical University, Saulėtekio al. 11, LT-10223 Vilnius, Lithuania
3. Department of Engineering Mechanics, Vilnius Gediminas Technical University, Saulėtekio al. 11, LT-10223 Vilnius, Lithuania; Institute of Mathematics and Informatics, Vilnius University, Akademijos g. 4, LT-08663 Vilnius, Lithuania