Joint member angle limits of composite beams and CFT square columns

LEE Seung-Jo¹, LEE Kang-Guk ²

(1. Department of Architecture, Chosun College of Science & Technology, Gwangju 501-744, Korea;
2. Research Center for Urban Affair, Kyungil University, Gyeongsan 712-701, Korea)

Abstract:This work aims to understand the relationship between the member angle limit and the energy ratio for 24 test samples of composite beams and CFT square steel tube columns. This work also compares the formula applicability for member angle limit with the previous test result to provide the basic data for the design of composite beam-CFT column. The evaluation of the member angle limit was performed with concrete compressive strength ( =22.16 MPa, 30.49 MPa), breadth-to-thickness ratio (B/t=25.0, 33.3, 43.5), and axial capacity ratio (N/N₀=0, 0.3, 0.4, 0.5) as the main variables of the test samples. For the relationship between the member angle limit (R_u) and the energy ratio (E_S/E_C), the test result shows that the energy ratio becomes lower as the axial capacity ratio and the breadth-to-thickness ratio increase. The energy ratio is lower for the Type B test sample compared with that of Types A and C. For the formula suggested by SATO, the test samples are distributed evenly for comparison between test values and the member angle limit; however, other formulas indicate a deviation. Specifically, for the comparison between R_u,cal and R_u (Test), Maeda’s formula shows severe deviation.

Key words:square steel tube; axial capacity ratio; member angle limit; breadth-to-thickness ratio