Flexural mechanism and design method for precast concrete splice slabs with welded junction plates

The joints of precast splice slabs significantly impact their flexural bearing capacity. This paper introduces a novel type of precast splice slab, termed the precast concrete splice slab with welded junction plates. A flexural loading test was conducted on 10 specimens (including eight precast splice slabs, one precast slab, and one cast-in-place slab). The main conclusions of the test are as follows. Severe damage barely occurred at the joint and at the interface between the precast unit and the cast-in-place concrete. The specimen produced flexural type vertical cracks in the tension zone and transverse cracks in the compression zone. When some longitudinal rebars in the precast unit of the specimens were bent into an arc, the cracking and yield loads were lower than those of the ordinary precast or cast-in-place slabs. The incorporation of lap-splice rebar in the cast-in-place concrete improved only the yield load of the specimens, while the welding of additional rebar in the precast unit significantly enhanced both the cracking and yield loads. A design method for determining the flexural bearing capacity of the precast concrete splice slab with welded junction plates was established. Meanwhile, the force transfer mechanism of the junction plates needs to be further investigated to establish a more economical design method for the junction plates.