1. School of Engineering, Computing and Mathematics, University of Plymouth 2 , Drake Circus, Plymouth PL4 8AA, United Kingdom
2. School of Mathematical and Physical Sciences, The University of Newcastle 3 , Callaghan 2308, Australia
3. Department of Construction, Civil Engineering and Architecture, Università Politecnica delle Marche 5 , via Brecce Bianche 12, Ancona 60131, AN, Italy