Flatjack application on existing hollow concrete block masonry Guilherme Aris Parsekian, Jairo Borges Ferreira Júnior, Gláucia Maria Dalfré and Roberto Marcio da Silva MATEC Web Conf., 403 (2024) 04001 Published online: 16 September 2024 DOI: 10.1051/matecconf/202440304001