1. Department of Structures for Engineering and Architecture, University of Naples Federico II, Naples, Italy;
2. Department of Engineering, Telematic University Pegaso, Naples, Italy;
3. Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino FR, Italy;
4. Dipartimento di ingegneria strutturale e geotecnica, University “La Sapienza”, Rome, Italy