Novo sistema estrutural pré-fabricado para construção de edifícios de múltiplos pavimentos: análise experimental e analítica da ligação semirrígida

Abstract

The widespread use of precast structures in civil construction offers significant advantages, such as improved quality control, ease of execution, and reduced construction time, in addition to ensuring high strength and durability. However, their application still presents important challenges, particularly regarding the performance of structural connections. Unlike cast-in-place structures, in which the elements are executed as a continuous unit, precast systems are composed of independent components assembled on-site. This hinders the reproduction of the monolithic concept of cast-in-place structures and requires the use of more robust elements and additional devices that, together, form a connection, ultimately increasing the overall construction cost. In light of this context, the main objective of this research is to perform an experimental and analytical investigation of a semi-rigid beam-to-column connection during the assembly stage of a new precast structural system. For this purpose, a full-scale prototype was manufactured, assembled, and tested in the laboratory in collaboration with T&A Pré-fabricados, the company sponsoring the research. The results showed that the beam-to-column connection exhibited good structural performance for this construction stage. The first visible cracks only appeared after a load of 120 kN, whereas the service load is 104.35 kN. Furthermore, the connection demonstrated semi-rigid behavior, with an initial stiffness of 126.07 MN · m/rad, a secant stiffness at the SLS of 70.187 MN·m/rad, and a secant stiffness at the ULS of 40.360 MN·m/rad. In addition, the analytical model developed showed good agreement with the experimental results, presenting an initial stiffness of approximately 136.52 MN ·m/rad, about 8% higher than the initial stiffness obtained from the tests.