# A Story-Based Random Structure Modeling Method for Regional Buildings Earthquake Loss Estimation
## 3 SBRS Model Sampling Process
### Common Layout for Structures  
RC frame structures, RC wall-frame structures, and reinforced masonry structures account for many service structures. The layout of the RC frame structure is relatively simple; the key lies in the arrangement of the column network, and the structure is dominated by shear deformation under the effect of an earthquake, while the RC wall-frame structure combines the characteristics of the two structural systems of the frame and shear wall. The shear wall system is dominated by bending deformation. Shear walls and frame columns are the main lateral force-resisting members, and the former usually serves as the first line of defense against seismic effects. When encountering small seismic effects, shear  
Figure 5: Equivalent reconstruction of building plane. walls exhibit bending deformation to consume seismic energy; when encountering large seismic intensity, the attached beams and the bottom of the limbs of the shear walls are the first to be damaged, and the frame columns serve as the second line of defense, which play a role in the redistribution of the structural plastic internal forces. Therefore, the total cross-section of the lateral-resisting members on each story of a reasonably designed RC wall-frame structure is kept within a certain range from the floor area, as shown in Table 1, where \(A_{w}\), \(A_{c}\), and \(A_{f}\) are the cross-sectional area of shear walls, the cross-sectional area of framing columns, and the floor plane area, respectively. The shear wall arrangement should generally follow the following principles in the design of wall-frame structures:  
1. Shear walls should be arranged bi-directionally along the main axis of the building, and both should have a similar total lateral stiffness. 2. Shear walls should be evenly distributed in the floor plane, and the spacing should be manageable to ensure that the building cover has sufficient stiffness in its plane. 3. For a regular rectangular floor plan, the shear wall should be suitable to maintain basic symmetry along the longitudinal and transverse bi-directional plane centerline. 4. Shear walls should be set through the entire building height to avoid sudden changes in stiffness to form a weak structure story. 5. The cross-section of the shear wall should be simple and regular to avoid the appearance of a complex and shaped cross-section. 6. The ratio of the total height of the shear wall to its section height should be at least 3, and the section height of the wall limb should generally not be more than 8 m.  
The shear wall serves as a vertical load and resists lateral forces in the building structure. Furthermore, it demarcates and encloses distinct spaces within the building. High-rise wall-frame structures are usually combined with stairwells, elevator shafts, and other vertical access arrangements in the local formation of a relatively large stiffness of the approximate cylindrical structure, with the distribution of other parts of the building wall limbs to jointly resist seismic effects, wind loads, and other lateral forces. A wall-frame-structured office building is being referred to, with an example of a common layout shown in Figure 6. The gray-shaded portions of the frame columns and shear walls in the middle of the long limb shear wall can be opened according to the need for door openings; the dotted line part of the frame beams, secondary beams, and infill walls are not shown in the figure. Reinforced masonry structures mainly show shear-type damage under the effect of earthquakes, and according to the different ways of vertical load transfer and load-bearing walls, they can usually be divided into three kinds of load-bearing methods: transverse wall bearing, longitudinal wall bearing, and longitudinal and transverse wall joint bearing. Because the wall of a reinforced masonry structure has space separation and structural load-bearing functions, its internal layout is complex and variable, and it is challenging to judge the specific structural arrangement accurately.