## 7 Seismic Performance of Composite Building Structures
### Seismic Performance of Composite Buildings: State-of-the-Art
For the same research project, namely OPUS, [PERSON] et al. (2017) [104] analyzed the impact of material properties on the seismic performance of steel and steel-concrete structures. Various lateral-resisting systems and steel qualities were considered, with 15 structures designed. An accurate probabilistic procedure was developed to estimate failure probability and a model for the mechanical properties of European structural steel products was calibrated. The seismic behavior of steel-concrete composite buildings designed with Turkish design codes was investigated by [PERSON] (2022) [105]. Composite moment-resisting frame buildings with different numbers of stories were analyzed at high ductility levels. Nonlinear static and dynamic analyses were conducted to assess the lateral response, over-strength factors, and ductility factors. The examined composite frames exhibited excellent performance, surpassing design expectations. Section deformation capacities were also evaluated during dynamic and static analyses. Similarly, [PERSON] (2023) [106] examined the seismic behavior of steel concrete composite buildings where 5-, 10-, 15-, and 20-story framed structures were designed using concrete-filled steel tube columns. The buildings were designed with high ductility based on Turkish design codes regulations, and nonlinear static pushover and incremental dynamic analyses were applied. The nonlinear analyses showed that the composite framed structures had good performance, with high ductility and the ability to absorb seismic energy through inelastic deformations. [PERSON] et al. (2016) [107] examined structural system performance factors, such as strength and ductility for steel-concrete composite moment frames under seismic loads. They used new finite element formulations to analyze the behavior of composite moment frames, where archetype frames were designed according to seismic codes specifications and subjected to nonlinear static pushover and dynamic response history analyses to determine performance factors. Moreover, [PERSON] et al. (2023) [108] investigated the seismic performance of post-earthquake composite frame structures with varying damage levels. Nonlinear time history analysis was conducted on a ten-story steel-concrete composite frame, using peak ground acceleration (PGA) as a measure of seismic intensity and damage. The structure was subjected to different PGAs in the first stage, resulting in three damage levels. The analysis focused on inter-story drift ratios and plastic hinge ratios, which show a uniform distribution pattern across the damage levels. The structure was deemed safe based on residual inter-story drift ratios. The second stage examined the residual capacity of the structure in strong earthquakes. The results revealed that pre-existing damage could increase lateral deformation and reduce resistance capacity. The performance of composite frames with circular concrete-filled steel tube columns attached to composite beams made of steel and concrete was studied by [PERSON] et al. (2018) [109] under axial and lateral stresses. The effects of the beam-to-column stiffness ratio, axial compression ratio, and stiffness ratio on seismic performance were examined through the testing of seven frames. Discussions were held regarding the experimental findings, which included ductility, energy dissipation capacity, load-deformation responses, damage development, and stiffness degradation. Additionally, a finite element approach,considering geometrical and material nonlinearity, was developed and validated against the experimental results. [PERSON] and [PERSON] (2021) [110] investigated the performance of steel-concrete composite buildings under earthquake loads with different numbers of stories and different, according to Eurocode 8 regulations, ductility levels.