Experimental and Numerical Study on Fully Prefabricated Composite Walls with Integrated Rebar Box Connections

An integrated rebar box connection is proposed for the horizontal joints of fully prefabricated composite walls to simplify joint detailing and reduce on-site wet construction. Experimental tests and numerical analyses were conducted to evaluate the behavior of this connection. The results show that both specimens exhibited shear-dominated failure. The box connection and horizontal joint did not experience obvious fracture or pull-out failure, although local cover spalling, mortar crushing, and connector deformation were observed, suggesting effective force transfer between the upper and lower wall panels under the tested conditions. Compared with the cyclically loaded specimen, the monotonically loaded specimen exhibited higher peak load and larger deformation capacity under monotonic loading, whereas the initial stiffness was similar. The numerical results agree reasonably well with the experimental responses. The parametric finite element analyses indicate that increasing the integrated rebar diameter, the longitudinal reinforcement ratio in the rib columns, the concrete grid strength, and the axial compression ratio improves the load-carrying capacity of the wall, although a higher axial compression ratio reduces ductility. The proposed connection shows promising potential for use in the horizontal joints of fully prefabricated composite walls, and further studies with additional specimens and comparative connection details are warranted.