## 5 Conclusions  
In this study, based on the cyclic loading tests and the finite element analysis, the load-bearing capacities and deformation performances were carefully analyzed for two different reinforced concrete columns with different diameters and reinforcement bar arrangements but with the same longitudinal reinforcement ratios. And three types of bond-slip models--full bonding, pull-out bond failure, and splitting bond failure-were used to analyze the effects on the mechanism and deformation behavior of RC column bending damage. The obtained conclusions from this study are as follows:  
* The load-bearing capacity and deformation performance of reinforced concrete columns is significantly affected by the diameter and arrangement of reinforcing bars, despite the longitudinal reinforcement ratios are same. The reinforced concrete column showed a 3.5% drift of high deformation capacity when using large-diameter and low-density bar arrangements. However, significant degradation of the deformation capacity to a 1.5% drift was observed in the reinforced concrete column with the small-diameter and high-density bar arrangements.
* In the cyclic loading test, despite being subjected to symmetrical hysteretic loadings, the RC column with small-diameter and high-density bar arrangements results in the splitting bond failure of the reinforcements. And in the loading directions it results in pronounced asymmetrical damage induced in the longitudinal reinforcements, ultimately leading in localized damage within the RC columns.
* By employing the bond-slip model proposed in this study in finite element analysis, the load-bearing capacity of RC columns can be reproduced with high precision. When using the pull-out model, the analytical error for the maximum load capacity of Case-1 is approximately 8% to 11%. In contrast, when using the splitting model, the analytical error for the maximum load capacity of Case-2 is less than 3%. Moreover, the damage condition of the reinforcement is also replicated.
* Furthermore, pinching phenomena observed in unloading hysteresis curve of force-displacement relationship also can be reproduced by employing an appropriate bond-slip model. Thus, it enables to verify the energy dissipation during earthquakes.
* The RC column with small-diameter and high-density bar arrangements result in the splitting bond failure along the longitudinal reinforcement bars, which leads the RC column to change the failure mode from the bending deformation mode to the rocking deformation mode.  
These research findings provide valuable insight into the load-bearing capacity and de-formation performance of reinforced concrete columns and the effects of bond-slip on seismic behavior. The proposed model provides an advanced prediction of the seismic  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Case-1 (PULL-OUT)**} & \multicolumn{3}{c}{**Case-2 (SPLITTING)**} \\ \hline  & **EXP** & **ANA** & **ERROR** & **EXP** & **ANA** & **ERROR** \\ \hline + & \(119.81\) kN & \(109.30\) kN & \(8.77\%\) & \(82.20\) kN & \(83.09\) kN & \(1.08\%\) \\ \(-\) & \(-124.21\) kN & \(-110.36\) kN & \(11.16\%\) & \(-81.43\) kN & \(-78.92\) kN & \(3.08\%\) \\ \hline \hline \end{tabular}
\end{table}
Table 4: Comparison of Experimental and Analytical Results for Lateral Force.  
behavior of RC structures and the improvement of seismic resistance of social infrastructure facilities against earthquake disasters.  
Conceptualization, G.W., P.S. and E.E.T.; methodology, G.W. and P.S.; software, P.S.; validation, G.W. and P.S., investigation, P.S. and G.W.; resources, G.W. and P.S.; data curation, P.S.; writing--original draft preparation, P.S. and G.W.; writing--review and editing, G.W., P.S. and E.E.T.; visualization, P.S.; supervision, G.W.; funding acquisition, G.W. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The authors declare no conflict of interest.