# Study of Effective Length Factor of Frame-Core Wall Structure with Cross-Layer Columns
## 3 FE Model Setting  
### Ordinary Frame-Core Wall Structure Model  
The calculation example of this study adopts a frame-core wall structural system, and the structural plan size is 45 m \(\times\) 27 m. The spacing of frame columns is 9 m, and concrete-filled steel tube members are utilized. The frame beams are H-shaped steel beams. The plane size of the core wall in the center of the structure is 27 m \(\times\) 9 m, and the width of the hole is 2.0 m. The overall height of structure H is 120 m, with 28 floors. The height of the 1 st-3 rd floors is 5 m, while the height of the rest of the floors is 4.20 m. The layout of the frame-core structure is shown in Figure 4.  
To investigate the influence of the number of cross-stories on the effective length factor, four models were built on the basis of the original model. In Model 1 and Model 3, the 1 st to 2 nd floors are the cross-story area. In Model 2 and Model 4, the 1 st to 3 rd floors are the cross-story area. Model 1 and Model 2 are cross-story columns between columns C9 and C12. Model 3 and Model 4 are the cross-layer columns between columns C1 and C5. The first-floor structural arrangement of these four frame-core wall structures is shown in Figure 5.  
Figure 4: Ordinary frame–core wall structure. (**a**) Three-dimensional schematic of frame–core wall structure; (**b**) first floor plan of frame–core wall structure/mm. Figure 3: Variation in frame buckling load correction factor \(\gamma\) with stiffness eigenvalue \(\lambda\). To ensure the accuracy of the analysis results, the cross-sectional specifications of members were gradually adjusted based on the rationality of the structural design, the requirements of the design conditions, and code standards. The minimum thickness of the shear wall is 250 mm, the height of all connecting beams is 1000 mm, and the concrete strength grade is C40\(\sim\)C60. The minimum cross-sectional size of concrete-filled steel tubular column is \(\square\)700 \(\times\) 20 mm, the steel material used is Q355B, and the concrete strength grade is C40-C50. The minimum cross-sectional size of the H-shaped section steel frame beam is H650 \(\times\) 300 \(\times\) 18 \(\times\) 25 mm, and the steel material is Q355B. The variation in shear wall thickness, cross-section size of members, steel thickness, and material strength grade with structural height are shown in Table 1. The thickness of the floor slab is 120 mm and the strength grade of concrete is C30. The minimum thickness of the shear wall is 250 mm, the height of all connecting beams is 1000 mm, and the concrete strength grade is C40-C60. The minimum cross-sectional size of concrete-filled steel tubular column is \(\square\)700 \(\times\) 20 mm, the steel material used is Q355B, and the concrete strength grade is C40-C50. The minimum cross-sectional size of the H-shaped section steel frame beam is H650 \(\times\) 300 \(\times\) 18 \(\times\) 25 mm, and the steel material is Q355B. The variation in shear wall thickness, cross-section size of members, steel thickness, and material strength grade with structural height are shown in Table 1. The thickness of the floor slab is 120 mm and the strength grade of concrete is C30. The finite element model was established in ABAQUS, in which the frame beam and column are simulated by B31 beam elements, the shear walls are simulated by S4R elements, and the floors are rigid slabs [23]. The mesh size of the beam, column, and wall elements is about 1000 mm, and the continued reduction in the mesh size has little effect on the results but the computation time increases significantly. The fixed support is simulated by constraining 3 translational degrees of freedom and 3 rotational degrees of freedom at the bottom of the columns. ABAQUS software-based linear elastic buckling BUCLK analysis was undertaken of the working conditions. The steel constitutive model is an ideal elastic-plastic model, and the Concrete Damaged Plasticity (CDP) constitutive model is used for concrete.