单人步行荷载模型研究

Load model for a single pedestrian

对于大跨轻柔结构,人-结构竖向相互作用较为显著,要准确预测结构人致响应,需建立更加精细的单人步行荷载模型。在单自由度弹簧、质量和阻尼(SMD)模型中,引进包含亚谐分量的内部自激励,建立了更加精细的ASMD模型Ⅱ,并对其进行了实验验证。结果表明:当结构自振频率处于亚谐共振区时,需考虑亚谐分量的影响,其影响随人/结构质量比的增加更显著,忽略亚谐分量会导致计算结果偏小;处于倍频共振区时,不考虑人-结构相互作用的共振响应预测结果偏于保守;相比之下,ASMD模型Ⅱ能更好的预测结构人致竖向动力响应。

For large span lightweight structures,the human-structure vertical interaction is significant,so that a more precise walking load model is needed to predict the human-induced vibration more accurately. An ASMD model Ⅱ which consist of a single degree of freedom spring mass damping（SMD） system and an internal actuator was built and verified by experiments. The results show that when the natural frequency of a structure falls into the sub-harmonic resonance region,the impact of sub harmonic component,should be considered,otherwise,the calculation results will incline to be small.When the natural frequency of the structure falls into the main-harmonic resonance region,a pure moving force model will be conservative in its predictions as it does not consider the interaction between the pedestrian and the moving bridge surface.In contrast,the ASMD model Ⅱ can better predict the human-induced vertical responses of the structure.