## 3 Seismic Behavior of Steel-Concrete Composite Shear Walls
### Seismic Behavior of Steel-Concrete Composite Shear Walls: State-of-the-Art
Two-dimensional FEM models and fiber-based FEM models were recommended for simulating seismic response, while three-dimensional FEM models were recommended for further parametric studies on structural behavior and design. Additionally, [PERSON] et al. (2015) [47] developed a novel lateral force-resisting system comprising high-strength concrete and a steel plate. Tests were conducted to analyze the response of this composite shear wall to cyclic loading. The axial load ratio and tie bar spacing were investigated. The specimens displayed high strength, deformation capacity, and flexure-dominated behavior. The primary failure mode involved the local buckling of steel plates and compressive crushing of concrete. An LS-DYNA ([[https://lsdyna.ansys.com/](https://lsdyna.ansys.com/)]([https://lsdyna.ansys.com/](https://lsdyna.ansys.com/))) finite element model was created by [PERSON] et al. (2015) [48] to model the cyclic behavior of flexure-critical steel-plate-concrete composite shear walls. Validation was performed using data from tests on composite wall pairs. The damage to the walls included cracking, crushing of infill concrete, and the buckling of steel faceplates. It was found that the model accurately predicted force-displacement responses, damping ratio, and damage distribution. Moreover, [PERSON] and [PERSON] (2016) [49] examined the behavior of composite sandwich walls, composed of two steel plates filled with ultra-lightweight cementitious material. Compression tests on different height composite walls revealed that J-hook connectors provided similar resistance and unloading behavior as overlapped-headed studs. J-hook connectors improved composite action, prevented local buckling, and showed a reasonable correlation with test results when included in predictive methods. [PERSON] et al. (2014) [50], based on a fiber section analysis approach, developed a program that analyzes the moment-curvature behavior of concrete-filled steel-plate composite shear walls. The program's accuracy was verified against test results, and a parametric study was conducted on 6379 configurations. Simplified formulas were developed based on the study's results, which can be used to calculate the drift capacities and ductility of composite shear walls. Furthermore, experimental and numerical analyses were conducted on low shear span ratio dovetailed profiled steel-concrete composite shear walls subjected to axial and cyclic lateral loads by [PERSON] et al. (2022) [51]. The results showed that all specimens failed in a ductile manner with a flexure-shear mixed mode. The lateral stiffness increased with higher thickness ratios, while deformability and energy dissipation capacity decreased. It was found that simplified models accurately estimated the lateral resistance of these composite walls. Four full-scale experiments were conducted by [PERSON] et al. (2022) [52] to evaluate the seismic performance of double-skin composite walls under earthquakes. The experimental results showed that these specimens had similar damage and flexural failure modes. Additionally, increasing boundary column thickness improved strength but decreased displacement ductility, while increasing the axial compression ratio improved strength but reduced ductility and energy dissipation cycles. Moreover, [PERSON] et al. (2021) [46] analyzed the behavior of concrete stiffened steel-plate shear walls with a reinforced concrete panel and a gap between the panel and steel frame. The reinforced concrete panel thickness greatly affects the shear capacity and ultimate strength of these composite walls, prevents elastic buckling, and allows lateral load through shear yield. The results showed that these composite walls and steel-plate shear walls exhibit different behaviors since for the latter type, the steel plate undergoes elastic buckling to resist lateral load. Furthermore, concrete-stiffened steel-plate shear walls offered higher initial elastic stiffness, shear capacity, ultimate strength, ductility ratio, and energy absorption compared to steel-plate shear walls.