行走激励下大跨度楼板振动的最大加速度响应谱方法

人的走动引起的楼板振动是大跨度楼板正常使用极限状态设计中需要考虑的重要问题,现行规范给出的静力挠度控制并不能充分体现大跨度楼板正常使用的内在要求。本文根据实测有代表性的落步曲线,采用ELLINGWOOD方法构造激励函数,进行了大量的时程分析计算,得到了不同阻尼、跨度和边界条件下梁板结构振动的最大加速度响应谱,分析了该响应谱对计算所采用的振型阶数、跨度、阻尼、边界条件等因素的敏感性,从而得到了加速度响应谱的包络曲线,给出了人走动引起梁振动的简化计算方法,本文提出的方法避免了时程分析在荷载处理上的麻烦,计算得到的结果与时程分析的结果有较好的一致性。

Peak acceleration response spectrum of long span floor vibration by pedestrian excitation

Floor vibration due to human activities is an important problem in serviceability design of the light and flexible structures. Static deflection limits stipulated in current design codes can not sufficiently meet the needs of the floor serv iceability. Through the method proposed by ELLINGWOOD, the loads acting on floor were formed using typical footfall traces. Then,after a large amount of dynamic simulations on beams of different modes, spans, damping and boundary conditions, the dynamic response spectrum of floor to realistic pedestrian excitation was achieved and based on which a response spectrum method was presented. To justify the validity of the method, sensitivity analysis was carried out to clarify the effects of such factors as mode selection, span, damping and boundary conditions. Through envelope curves presented in this paper, one can easily calculate the maximum acceleration of the floor vibration under the pedestrian loads. The advantage of the method is that it can give an approximate result while avoiding the trouble in defining loads in time history analysis.