Yu-Chen OuBui, Cong-ThanhCong-ThanhBuiLin, Yu-TingYu-TingLinYen, Sheng-ISheng-IYen2025-06-172025-06-172025-05https://www.scopus.com/record/display.uri?eid=2-s2.0-105004413497&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/730096This research proposes a standardized arrangement of longitudinal reinforcement using Grade 690 MPa (100 ksi) high-strength steel and D32 (No. 10) or D36 (No. 11) large-diameter threaded bars to alleviate reinforcement congestion and construction difficulties. Four full-scale column specimens with the proposed standardized arrangement were tested using double-curvature lateral cyclic loading to examine their seismic performance. Test results showed that all the columns exhibited a combined axial and flexural failure mode, with ultimate drift ratios ranging from 4.07 to 5.98%, ratios of measured to nominal moment strength based on actual material strengths ranging from 1.18 to 1.51, and relative energy dissipation ratios satisfying the requirement of ACI 374.1-05. No shear or bond-splitting failures were observed. Based on the test data from this research and the literature, two modifications were proposed in the calculation of ℓd to relax the requirement of 1.25ℓd ≤ ℓu/2 as required by ACI 318-19.bond splittingcolumnshigh-strength reinforcementlarge barlongitudinal reinforcementseismic[SDGs]SDG11journal article10.14359/51745668