Load-bearing and failure behavior of welded horizontal joints in prefabricated shear wall structures

Prefabricated concrete structures offer advantages in construction efficiency and environmental performance, but the mechanical behavior of dry-connected horizontal joints, especially welded connections between shear walls and floor slabs, remains insufficiently understood. This study presents a systematic experimental and numerical investigation into the seismic performance of such horizontally welded joints. Two full-scale joint specimens (HJSP1 representing an outer wall-floor connection and HJSP2 representing an inner wall-floor connection) were designed, fabricated, and subjected to quasi-static reversed cyclic loading. Key quantitative findings include the welded joints exhibited an average peak load capacity of approximately 330 kN and an ultimate displacement of 40–44 mm, with displacement ductility coefficients greater than 3.0. The average initial cracking stiffness was about 60–65 kN/mm, which degraded progressively under cycling. Failure was characterized by a combined shear-flexure interaction involving shear yielding of the connecting plates and eccentric compressive crushing of the wall boundary elements. A three-dimensional finite element (FE) model was developed using the Concrete Damaged Plasticity model in ABAQUS and validated against the test results, showing good agreement in load-displacement response. Parametric studies revealed the significant influences of axial compression ratio and shear-span ratio on the failure mode and capacity. The primary novelty of this work lies in its integrated experimental and numerical analysis of horizontally welded joints under combined shear and eccentric compression, providing fundamental insights and a validated modeling tool for the design of dry-connected joints in prefabricated shear wall systems.