ABSTRACT
For the finite element (FE) simulation of reinforced concrete (RC) structures, the concrete-steel “bond” is crucial, especially for the precast structural connection. Despite the wide adoption in practice, there is an insufficient understanding of the “bond” behaviour within the grout sleeve connector, and current design of the connector parameters is largely based on empirical data from the experiment. For seismic applications the ductility of the connection region is a key and this is dependent upon the deformability of the connector; however information about the overall deformation capacity of a sleeve connector is scarce in the existing literature. On the other hand, the ductility of a connection region depends not only on the deformation capacity of the connector itself but also on the interaction between the connector and the surrounding concrete. To cater for these features, a computation model should be capable of representing both the “microscopic” interior rebar-grout-sleeve interaction and the more “macroscopic” exterior sleeve-concrete bond behaviour. This paper presents an overview of an equivalent transitional layer approach which adopts a perfect “bond” at the groutrebar interface and representing macroscopic “bond strength” “slip” through the strength and deformation of the transition layer. The experimentally observed (macro) bondslip phenomenon is realised through modifying the stressstrain behavior of the solid transitional elements with mesh-objective equivalent properties The proposed bond scheme is verified by FE simulation in ABAQUS for various scenarios included a general pullout test, a grout sleeve connector test, and a precast column test.
