## 2 Experimental Procedure  
### Specim Design  
An experimental program was conducted to understand the high-strength bridge column's seismic behavior and compare it with the conventional RC bridge column. A total of six full-scaled bridge columns, including five high-strength bridge columns and one conventional RC column, were designed and subjected to a quasi-static cyclic loading test under a constant axial load. After completing the bridge column test, one single-bay high-strength frame (multi-column bent) was designed and tested under quasi-static cyclic loading. The prototype of the RC bridge column is a typical rectangular bridge column in Taiwan. The dimensions and design of the specimen reinforcements are shown in Figure 1. Specimen BMRC1 was designed as a control specimen with normal-strength materials. It has a 600 mm \(\times\) 600 mm square cross-section and is reinforced with 16 D25 (No. 8) bars and transversely reinforced with D13 (No. 4) crossties and 135-degree seismic hooks. On the other hand, specimens NEWRC1, NEWRC2, NEWRC3, NEWRC4, and NEWRC5 are composed of high-strength materials, have a square cross-section of 500 mm \(\times\) 500 mm, and are reinforced with 12 D25 (No. 8) longitudinal bars and transversely reinforced with D13 (No. 4) crossties and 135-degree seismic hooks. The clear height of all the column specimens is 3600 mm, while the thickness of the concrete cover is 40 mm. The longitudinal reinforcement ratio for BMRC1 was 2.26%, whereas, for all the NEWRC columns, it was 2.44%. Although the longitudinal reinforcement ratio between BMRC1 and NEWRC columns is similar, the cross-sectional area and longitudinal rebar vary. Due to this, specimen NEWRC1 has a 30.5% reduction in column cross-sectional area, 25% reduction in longitudinal reinforcement area, and 35.7% reduction in the transverse reinforcement area compared with specimen BMRC1. The primary objective of having different specifications for BMRC1 and NEWRC1 is to investigate whether a similar force-deflection response can be achieved with the reduced cross-sectional area, longitudinal reinforcement area, and transverse reinforcement area. The experimental parameters used for determining the seismic behavior of the NEWRC columns are the spacing of the transverse reinforcements, the axial load ratio, and transverse reinforcement strength. In this study, the amount of transverse reinforcement for BMRC1 was 1.08%, while for NEWRC columns, it ranged from 0.344% to 1.03%. The transverse reinforcements' spacing was kept at 100 mm for BMRC1, NEWRC1, NEWRC4, and NEWRC5, which is less than five times the diameter of the longitudinal bars. However, for NEWRC2 and NEWRC3, the transverse reinforcement spacings were increased to 200 and 300 mm, respectively, which is higher than five times the diameter of the longitudinal bars. In the literature, premature bar buckling has often been identified as the main factor for the failure of the high-strength column [30]. In this view, the results from NEWRC1, NEWRC2, and NEWRC3 will provide an insight into the influence of transverse spacing on the high-strength columns' seismic performance. Figure 1: Section details for the BMRC1, NEWRC columns, and NEWRCF. Unit: mm. Furthermore, to investigate the effects of the axial load ratio on the seismic performance, the axial load on the NEWRC4 was twice that of NEWRC1. The frame specimen was constructed and tested after completing the BMRC1 and NEWRC columns test; therefore, the design of the frame specimen is provided separately. In the frame specimen NEWRCF, both the columns (piers) had the same cross-sectional design and detailing as the NEWRC1. The primary purpose of experimenting with the frame specimen is to investigate whether the single column behavior can be reflected in the multi-column bent frame structure. However, the clear height and clear span for column and beam of NEWRCF were 4000 mm and 5500 mm, respectively. The beam had a cross-section of 900 mm \(\times\) 1100 mm and was reinforced with eight D25 (No. 8) bars and 32 D13 (No.