## 5 Concrete-Encased Steel Column Behaviors under Cyclic Loads
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Author** & **Type of Analysis** & **Achievement of Analysis** \\ \hline [PERSON] et al., 2021 & Seismic performance of steel-reinforced concrete composite columns & CES columns with non-seismic detail and low axial loads controlled by flexural tension appear to meet the acceptance criteria \\ [PERSON] et al., 2021 & Seismic behavior of large-size encased cross-section steel-reinforced columns [PERSON] et al., 2011 & The influence of the steel ratio is more significant under a low axial load ratio \\  & Ductility evaluation of concrete-encased steel & When using a sufficient amount of steel, CES columns have remarkable \\ [PERSON] et al., 2014 & Study on seismic behavior of fully encased steel-concrete composite columns & Under seismic load, the steel-concrete composite columns \\ [PERSON] and [PERSON], 2012 & Study on behaviors of steel-reinforced concrete columns & The long columns’ carrying capacity \\ [PERSON] et al., 2012 & Flexural behavior of SRC columns under axial and bilateral loading & The axial load ratio was the most influencing factor on the ductility of columns \\ [PERSON] et al., 2016 & Experimental study on steel reinforced concrete columns under cyclic lateral force & The axial compression ratio has an impact on the deformation capacity and the energy dissipation capacity \\ [PERSON] et al., 2019 & Study on ultimate load and ductility of concrete-encased steel composite columns & A larger load ratio is shown to reduce energy dissipation and deformation capacities \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Summary of some related previous research. seismic behavior preceding concrete cover spalling [41]. It has been demonstrated that a bigger steel section size results in superior ductility and less stiffness degradation when considering the steel area ratio. It was found that structural steel is more advantageous in the event of a big axial load [41], while another researcher notes that the influence of the steel ratio is more significant under a low axial load ratio [40]. One other factor that has an impact on the seismic behavior of the CES column is the embedded depth ratio. The steel section of the CES column is embedded in the foundation. This length is known as \(h_{b}\). The height of the steel section is also known as the \(h_{a}\). The ratio of the embedded length of the steel section to section height is known as the embedded depth ratio, and it presented as \(h_{b}/h_{a}\). To preserve the CES column's strength capability and seismic behavior, an appropriate steel embedding depth is needed [42]. Also, the steel-embedded depth ratio for the CES column subjected to monotonic loading has been studied, and it was found that 1.67 was a suitable value for an ordinary CES column [43]. However, it is recommended that the minimum steel embedded depth ratio for the CES columns should be a minimum of 2.5 in order to take safety precautions into account [36]. For this reason, the Chinese specification [44] prescribes a minimum embedded depth ratio of 3 for the CES columns. Another parameter that has an impact on the seismic behavior of the CES column is the shear connector. On the CES composite specimens with steel shear connections, numerous analytical and experimental investigations have been carried out to examine the behavior of shear connectors under axial loads and combinations of axial and seismic loads. The findings demonstrated that, in comparison to non-seismic shear capacities, seismic loads cause a 40% decrease in the shear stud's capacity. This reduction happens as a result of seismic fatigue of the weld/connector materials and concrete crushing, which moves the stress distribution up the connector's shank and onto its head. This increases the connector's bending stresses and leads to earlier failures [12]. The shear stud capacity was unaffected by the studs' shear connectors' initial bending. Similar to static capabilities, the concrete strength had an impact on the seismic shear capacity of the studs [45].