空腹式延性桁框结构探讨

Study on Special Truss Moment Frames with Vierendeel Web Members

在桁框结构的桁架跨中设置空腹式消能段是一种延性桁框结构。针对该结构体系,首先推导了消能段的极限抗剪承载力,然后提出了桁框结构的简化计算模型,并根据我国抗震设计准则给出了确定消能段长度的计算方法和构造要求。采用此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。最后采用有限元方法进行了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延性桁框结构的延性、耗能能力、承载能力和安全储备,使其抗震性能明显优于普通桁框结构。提供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。

Arranging energy dissipation segment with vierendeel web members in the midspan of a truss moment frame can make it become a kind of special truss moment frame.Firstly,the ultimate shear-bearing capacity of energy dissipation segment is derived.Secondly,the calculation model of structures,methods to determine the length of energy dissipation segment and detailing requirements are presented.The proposed method can control the yield moment and failure mode of special truss moment frames accurately,and achieve the target which all stories yield synchronously under horizontal earthquakes,so consume energy fully.Finally,monotonic and cyclic tests are verified by finite element method.Results show that,energy dissipation segment with reasonable length can significantly enhance ductility,energy dissipation capacity,load carrying capacity and safety margin of special truss moment frames,and its seismic behavior is obviously superior to that of truss moment frames.The proposed method in this paper has higher precision,and can realize structural optimization design in the premise of ensuring energy consumption of energy dissipation segments.