X形弱腹杆式延性桁框结构探讨

X形弱腹杆式延性桁框结构是一种新型抗震结构体系，针对该结构体系，推导消能段的受剪承载力，提出结构简化计算模型，并根据我国抗震设计准则给出确定X形弱腹杆截面和消能段长度的计算方法及构造要求。采用上述方法确定的消能段可以精确控制延性桁框结构的屈服时刻和破坏模式，并实现水平地震作用下各楼层同步屈服，充分耗能。最后采用有限元分析方法进行单向和循环加载分析与验证，结果表明：合理的消能段长度可以显著提高桁框结构的延性、耗能能力、承载能力和安全储备，抗震性能明显优于普通桁框结构；弱腹杆截面和消能段长度的计算方法具有较高的精度，可以在确保消能段耗能的前提下实现结构的优化设计。

Study on special truss moment frames with weak X-diagonals

Special truss moment frames with weak X-diagonals is a new kind of seismic structure system. Firstly, the ultimate shear capacity of energy dissipation segment was derived. Secondly, the calculation model of structures, methods to determine the cross section of weak X-diagonals, the length of energy dissipation segment and detailing requirements were presented. The presented method can control the yield time and failure mode of special truss moment frames accurately, and achieve the target that all floors yield synchronously under the horizontal earthquake with energy fully consumed. Finally, monotonic and cyclic simulations with finite element method are conducted. Results show that, reasonable length of energy dissipation segment can significantly enhance the ductility, energy dissipation capacity, load carrying capacity and safety margin of special truss moment frames, and its seismic behavior is obviously superior to truss moment frames. This paper provides methods with higher precision that can obtain the structure optimization design in the premise of ensuring energy consumption of energy dissipation segment.