Discussion of “Concrete structures: contribution to the safety assessment of existing structures by Couto, D.; Carvalho, M.; Cintra, A. and Helene, P. Rev. IBRACON Estrut. Mater. 2015, vol.8, n.3, pp. 365-389” - Santos, Daniel Miranda dos; Stucchi, Fernando Rebouças; Beck, André Teófilo (Revista IBRACON de Estruturas e Materiais, 2015)