## 5 Conclusions  
The study discussed an experimental investigation and numerical modeling of large-scale high-strength bridge columns. The test parameters were the material strength, axial load ratio, and spacing of transverse reinforcement. Based on the results of this experimental study and numerical modeling, the following conclusions are drawn:  
1. The failure process of NEWRC columns was similar to that of the BMRC1 column and consisted of four stages: cracking, yield, ultimate, and failure. Longitudinal rebar buckling was identified as the contributing factor for all the column's failure, and it was influenced by the spacing of the transverse reinforcement. NEWRC1 had a similar force-displacement relationship as BMRC1 despite a reduced cross-sectional area, longitudinal reinforcement area, and transverse reinforcement area. 2. In comparison among the NEWRC specimens, the ductility ratio of NEWRC1, NEWRC4, and NEWRC5 were higher than 5, thus satisfying the MOTC-2020 code requirement. On the other hand, for NEWRC2 and NEWRC3, it was lower than 5. The results suggested that transverse reinforcement's spacing greatly influenced its ductility ratio and failure pattern, especially in the elastoplastic zone. 3. The energy dissipation capacity and equivalent viscous damping ratio of NEWRC columns are compared with BMRC1. Hence, the results suggested that using HSC and HSR can result in lower energy dissipation and equivalent viscous damping ratio compared to conventional RC columns. For NEWRC columns, within a certain range, a higher axial load ratio, such as in NEWRC4, resulted in an increased energy dissipation capacity. 4. NEWRC5 had a similar force-displacement, energy dissipation, viscous damping ratio, and residual drift ratio as NEWRC1. Hence, the replacement of HSR transverse reinforcement with NSR did not necessarily influence the column's seismic performance under a low axial load. Therefore, the combination of NSR for transverse reinforcement and HSR for longitudinal reinforcement in bridge columns can be more economical. 5. The ACI 318-19 code equations for minimum transverse reinforcement consider the strength of transverse reinforcement; however, from the comparison between NEWRC1 and NEWRC5, it was observed that it would increase the overall volume of reinforcement which would be unnecessary, especially under the low axial load. 6. NEWRCF had a similar failure pattern as NEWRC1, with the leading cause of failure being the buckling of the longitudinal rebar. Overall, NEWRCF had a good seismic response, as a ductility ratio of 5.19 was recorded, and the residual drift ratio was below 1%, even at a higher drift ratio of 3%. Figure 19: Comparison of the experimental and simulation results for NEWRCF. The numerical model developed in OpenSees using a buckling shear spring was able to predict the seismic performance of the high-strength columns precisely. Moreover, the model also considered the material strength, transverse reinforcement spacing, and axial load ratio and predicted the shear-strength degradation due to longitudinal rebar buckling with high accuracy. The proposed numerical model can further be applied to investigate the seismic performance of a broader range of high-strength columns in both buildings and bridges. Conceptualization, R.S. and K.-Y.L. ; methodology, K.-Y.L. and W.W.; software, R.S. ; validation, K.-Y.L. and R.S. ; formal analysis, R.S. ; investigation, R.S. ; resources, K.-Y.L. and W.W.; data curation, R.S. ; writing--original draft preparation, R.S. ; writing--review and editing, R.S. ; visualization, K.-Y.L. and W.W.; supervision, K.-Y.L. ; project administration, K.-Y.L. ; funding acquisition, K.-Y.L. All authors have read and agreed to the published version of the manuscript. The test program was made possible by research project funding granted by the Ministry of Science and Technology (MOST), Taiwan, under grant number MOST104-2625-M492-005 (PI: [PERSON], [PERSON]). Not applicable.