Numerical investigations of the steel-concrete load transfer mechanisms in earthquake resistant hybrid coupled shear walls

In earthquake resistant hybrid coupled shear walls, the overall overturning moments are resisted partly by the individual flexural action of these walls and partly by an axial compression/tension in the coupled concrete walls. Such a resistance mechanism implies however the transfer of large bending and shear forces in the steel coupling beams. The present contribution aims at studying through advanced finite element analyses the load transfer mechanism in beam-to-wall connections, including the stress distribution in the embedding concrete and the failure modes of the connections. Two types of connections are considered in the study. The first one assumes that the moment transferred by the embedded part of the coupling beam to the concrete shear wall is resisted by a couple of vertical forces, while the second configuration implements connection details with shear studs welded to the embedded part of the coupling beam and aiming at a transfer of the bending moment by a couple of horizontal shear forces. The final objective of the paper is to use the analysis results to investigate deeper the interaction between the local stress effects in the concrete wall due to the forces transferred from the beams with the global stresses coming from the overall bending of the walls, in order to optimize the performance of coupled system.