大跨度楼盖结构自振频率与人致振动舒适度关系研究

Study on the Relation of Natural Frequency and Vibration Serviceability of Large-span Floor Structures Under Crowd Loading

对大跨度楼盖结构的竖向基频与其人致振动响应之间的关系进行了研究。首先基于单人共振模型,给出了楼板人致振动响应的近似计算方法。然后考虑人群荷载在板上均匀分布,得到了各种边界条件下楼板的竖向自振频率与人致振动响应之间的关系。并以长沙南站高架候车层49m大跨度楼盖结构为例,通过调整支撑桁架的高跨比,得到了不同自振频率下楼盖结构的人致振动响应,并给出了满足舒适度要求的楼板竖向自振基频的限值。结果表明:当楼盖结构的竖向自振频率大于3.3Hz时,其人致振动舒适度一般能满足要求;在楼板的人致振动分析中,可根据刚度等效的原则通过增加混凝土板厚来考虑楼板装饰面层等非结构构件对结构动力特性的影响。

The relation between the vertical fundamental frequencies and the human-induced responses of large-span structures are systematically investigated in the paper.Based on resonance model under single pedestrian load,an approximate computing method of the responses of the floor is presented.Then the detailed relations between the vertical fundamental frequencies and the human-induced responses of the floor with various boundary conditions are obtained providing the crowds are uniformly distributed.Finally,take the 49 m span steel-concrete composite floor structure of the waiting floors of South Changsha Railway Station as an example,the responses of the floor of various frequencies under crowd loading are obtained by altering the height-span ration of the supporting steel trusses.The acceptable criterion limits are also suggested.It was found out that： the human-induced vibration serviceability of the structure generally can meet the design requirements when its vertical fundamental frequency is greater than 3.3 Hz;the effects of the nonstructural elements to the dynamic properties of the floor system should be considered by increasing the thickness of the concrete slab based on the principle of equal stiffness in the analysis of the human-induced vibration of the floor.