## 2 Introduction of Split Column Technology
### Comparative Analysis of Skeleton Curves  
Some scholars have designed ordinary reinforced concrete columns and reinforced concrete split columns for pseudo-static experiments based on the actual situation. The failure modes of ordinary reinforced concrete columns and reinforced concrete split columns have been studied. The seismic performance of various components, including ductility, rigidity degeneration, and energy dissipation capacity, is analyzed [25; 31]. The reinforcement details of column specimens are shown in Figure 3.  
In this paper, finite element analysis software ABAQUS is used to establish models for ordinary concrete columns (PTZ) and reinforced concrete split columns (FTZ), and each module is set up, including components, material properties, assembly, constraints, boundary conditions, analysis steps, and meshing steps. In the model, concrete is modeled using the three-dimensional eight-node reduced integration solid element (C3D8R), the steel bars are modeled using the three-dimensional two-node truss element (T3D2), and the clapboard is also modeled with the three-dimensional eight-node reduced integration solid element (C3D8R). The constitutive model for concrete adopts the plastic damage model, while the ideal double broken line model is used for the steel bars. The concrete constitutive parameters are shown in Figure 4, and additional plastic parameters for concrete are provided in Table 1. To ensure the accuracy of the simulation results, boundary conditions and load settings are kept consistent with the test. The bottom of the column is fixed, and the top of the column is subjected to axial pressure and horizontal displacement constraints. In the interaction module, the steel element is embedded in the concrete element through the built-in area (Embedded) in the module. The simulation model is shown in Figure 5.  
Figure 2: Strain distribution of split column concrete. Figure 4: The relationship between stress, damage factor, and inelastic strain. (**a**) Compression behavior. (**b**) Tensile behavior. Figure 3: Reinforcement diagram for each specimen. (**a**) PTZ. (**b**) FTZ. The skeleton curves of the split column and the whole column under both the test and numerical simulation are extracted, as shown in Figure 6. In the elastic stage, the horizontal load of the structure in the numerical simulation and the test is essentially the same. As the displacement increases, for PTZ, when the displacement reaches 55 mm, both the numerical simulation and the test show that the specimen reaches its peak at the same time. The horizontal peak in the test is approximately 245 kN, while the horizontal peak in the numerical simulation is 240 kN. As the displacement continues to increase, the decrease in horizontal load observed in the test becomes more apparent. When the displacement reaches 120 mm, the horizontal load decreases to 199 kN in the test. The numerical simulation shows that when the displacement reaches 120 mm, the horizontal load decreases to 223 kN. For FTZ, the numerical simulation shows that the horizontal load reaches a peak of 154 kN when the displacement reaches 61 mm. The test shows that the horizontal load reaches a peak of 159 kN when the displacement reaches 91 mm. As the displacement increases further, the decrease in horizontal load observed in the test becomes more noticeable. When the displacement reaches 120 mm, the test shows that the horizontal load drops to 131 kN, while the numerical model shows that the horizontal load drops to 143 kN. As shown in Figure 7, in the elastic stage, the load-displacement skeleton curves of FTZ and PTZ in the test are essentially consistent, and the load-displacement skeleton curve of PTZ in the numerical simulation is slightly larger than that of FTZ. The experiment shows that when the horizontal load reaches the peak, PTZ increases by approximately 54.1% compared to FTZ, while the numerical simulation shows that when the horizontal load reaches the peak, PTZ increases by approximately 55.8% compared to FTZ.