An Investigation of Bearing Capacity of High-Strength SRC Columns under Eccentric Axial Load

This paper investigates the eccentric compression performance of high-strength steel reinforced concrete (SRC) columns. In addition, the feasibility of the calculation codes used for the load-carrying capacity of these columns is verified by eccentric compression tests on 10 high-strength SRC columns with Q460 and Q690 steels and two normal SRC columns with Q235 steel. Moreover, the influence of the steel strength, relative eccentricity, steel ratio, and stirrup spacing on the bearing capacity and ductility of the specimens is analyzed. It was found that the bearing capacity and ductility of the specimens significantly increases when the steel strength increases from 276.5 MPa to 774.2 MPa; the bearing capacity of the Q690 SRC column is slightly higher than that of the Q460 SRC column. In addition, the ductility coefficient of the Q690 SRC columns is significantly higher than that of the Q460 SRC columns. It was also found that increasing the eccentricity and steel ratio can improve the ductility of the specimens and the smaller stirrup spacing can enlarge the contribution of Q690 steel under the ultimate bearing capacity. It is demonstrated that Eurocode 4-2004 and AISC360-16 codes significantly underestimate the test results. In contrast, JGJ138-2016 slightly underestimates the test results when the relative eccentricity is 0.2 but overestimates the test results when the relative eccentricity is 0.6. Furthermore, in order to maximize the contribution of Q690 steel under ultimate bearing capacity, the expanded parameter analysis is carried out using a finite element model. Following the analysis results, the suggestions for designing high-strength SRC columns under eccentric load are provided.

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