This paper studies the effect of adjacent braces interaction (ABI) on seismic and static performance of circular hollow section (CHS) unstiffened tubular connections under out-of-plane bending moment. A comprehensive comparison between CHS KK-connections (each chord side has two identical braces named adjacent braces) and the corresponding CHS X-connections (each chord side has one brace) is performed by experimental testing and finite element (FE) analysis, to evaluate the effect of ABI on the out-of-plane flexural behavior of CHS connections. The test results show that the load-carrying capacity of thin-walled CHS KK-connections (with ABI) is nearly 80% of that of the X-connections (without ABI). Moreover, experimental results indicate that CHS connections with ABI have better energy dissipation and ductility than CHS connections without ABI, which is further confirmed by the proposed load transferring mechanism model. FE parameter analysis results show that the effect of ABI on the moment-rotation curves and capacity is weak for CHS connections with chord radius-to-thickness ratio smaller than 9 and brace-to-chord angle smaller than 50°. But the influence of ABI is relatively larger for those CHS connections with the chord radius-to-thickness ratio larger than 10. Additionally, an equation for the capacity ratio of KK-connections to X-connections is proposed to consider the influence of ABI on the out-of-plane flexural capacity of CHS connections, and the equation has been verified by FE and testing results.

本文研究了在平面外弯矩作用下，相邻支撑相互作用（ABI）对圆形空心截面（CHS）非加筋管状连接的抗震和静态性能的影响。通过实验测试和有限元（FE）分析对CHS KK连接（每个弦侧具有两个相同的大括号，称为相邻大括号）与相应的CHS X连接（每个弦侧具有一个大括号）进行全面比较，以评估ABI对CHS连接平面外弯曲行为的影响。测试结果表明，薄壁CHS KK连接（带ABI）的承载能力几乎是X连接（不带ABI）的80％。此外，实验结果表明，与不带ABI的CHS连接相比，带ABI的CHS连接具有更好的能耗和延展性，所提出的载荷传递机制模型进一步证实了这一点。有限元参数分析结果表明，对于弦半径与厚度之比小于9且撑杆与弦角小于50°的CHS连接，ABI对弯矩-旋转曲线和通行能力的影响较弱。但是，对于弦半径/厚度比大于10的CHS连接，ABI的影响相对较大。此外，提出了KK连接与X连接的容量比的方程，以考虑ABI对连接的影响。 CHS连接的平面外抗弯能力，该方程已通过有限元和测试结果进行了验证。有限元参数分析结果表明，对于弦半径与厚度之比小于9且撑杆与弦角小于50°的CHS连接，ABI对弯矩-旋转曲线和通行能力的影响较弱。但是，对于弦半径/厚度比大于10的CHS连接，ABI的影响相对较大。此外，提出了KK连接与X连接的容量比的方程，以考虑ABI对连接的影响。 CHS连接的平面外抗弯能力，该方程已通过有限元和测试结果进行了验证。有限元参数分析结果表明，对于弦半径与厚度之比小于9且撑杆与弦角小于50°的CHS连接，ABI对弯矩-旋转曲线和通行能力的影响较弱。但是，对于弦半径/厚度比大于10的CHS连接，ABI的影响相对较大。此外，提出了KK连接与X连接的容量比的方程，以考虑ABI对连接的影响。 CHS连接的平面外抗弯能力，该方程已通过有限元和测试结果进行了验证。