高强钢组合K形偏心支撑钢框架弹塑性状态的层剪力分布研究

SEISMIC SHEAR OF K-TYPE ECCENTRICALLY BRACED STEEL FRAMES WITH HIGH STRENGTH STEEL IN ELASTO-PLASTIC STATE

  • 摘要: 高强钢组合偏心支撑钢框架结构中耗能连梁作为屈服构件采用普通钢(如Q345),而非耗能构件采用高强度钢材(如Q460),高强钢构件不仅有效降低了构件截面、节约钢材、降低造价,而且减弱了偏心支撑结构的刚度,使得层剪力分布状态与传统偏心支撑结构不同。为了研究这种新型结构在罕遇地震作用下的弹塑性层剪力分布状态,依据偏心支撑钢框架结构基于性能的设计方法设计了具有理想失效模式的5层、10层、15层和20层算例,并考虑了近场地震速度脉冲效应和远场地震加速度循环累计效应对结构的影响,采用动力时程分析方法计算结构在罕遇地震水准下的响应,根据结构弹塑性层剪力的平均值,提出了与我国规范相一致的弹塑性层剪力分布模式,并对比了已有的层剪力分布模式,该文建议的层剪力分布模式具有更高的精度,可为高强钢组合K形偏心支撑能量设计方法和塑性抗震设计理论提供参考依据。

     

    Abstract: Eccentrically braced steel frames composited with high strength steel (HSS-EBFs) use ordinary steel (e. g. Q345 steel) for links and high strength steel (e. g. Q460 steel) for non-energy dissipation members. The usage of high strength steel effectively decreases the section size of structural members, reduces the construction cost and weakens the stiffness of the EBFs. This leads to the difference in the distribution of story shear force from that of ordinary EBFs. In this study, four HSS-EBFs of 5, 10, 15 and 20 layers were designed with ideal failure modes to study the elastic-plastic story shear force distribution of HSS-EBFs under rare earthquakes. Meanwhile, the velocity impulse from near-field and the cumulative effect of the seismic acceleration from far-field were considered. The nonlinear time-history method was used to calculate the response of HSS-EBFs under rare earthquakes. Based on the mean value of the elasto-plastic story shear force, a distribution pattern of elasto-plastic story shear force consistent with national codes and standards was proposed, which was found to have a higher level of accuracy compared with other existing distribution patterns. The results of the current analysis provide a reference for energy design method and plastic seismic design theory of HSS-EBFs.

     

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