Investigations on the Estimation of Vibratory Properties of the R/C Floor Slab as Quantitative Indices of its Perceptible Vibrations

到目前为止，我们已经提出了预测钢筋混凝土楼板长期挠度的方法。并对已有的相关数据进行了分析，结果表明，板的长期挠度、自振频率和振幅这三个主要指标之间存在着密切的关系；此外，在本研究中，阻尼系数也是一个理想的冲击振动感知大小的标准指标，它也被证明与长时间挠度密切相关。最后，我们提出了方便的长时间挠度的近似公式，其值是估计上述任何指标所需的。其中，迄今所获得的主要研究成果如下：(1)有助于扩大我们所提出的关于先前频率和振动幅度的估计方程的有效范围，通过对6栋新建钢筋混凝土楼板的现场测量，又收集到了更多的现场数据。(2)关于阻尼系数：通过对有关观测数据的重新分析，尽管它们即使在相同尺寸的楼板上也有很大的散射，但它们的平均值与平均长时间挠度比之间存在着密切的相关性，例如，长时间挠度与板的短跨度的比率。(3)提出了一套近似的长时间挠度公式，使我们能够根据其精确的计算值容易地预测其实际量；它是由参数模型分析得出的，使用影响钢筋混凝土板挠度性能的主要因素作为其参数，通过标准的试验设计过程。

Hitherto we have proposed methods for predicting long-time deflections of r/c, e.i., reinforced concrete floor slabs. And attendant analyzes of the related data thus far obtained have revealed a close relationship among three major indices of slab behavior, i.e.long-time deflection, natural frequency and amplitude of vibration induced by walkers ; with those findings enabling the prediction of the above frequency and amplitude in a considerable simple manner.Besides, in the present research damping coefficient, also a desired standard index for perceptional magnitude of impactive vibration, proved to be strongly related as well to long-time deflection.Eventually we proposed convenient apprpximate formulas for long-time deflection whose values are needed for estimating any above index.Including these, main research results obtained to date are as follows :(1) Instrumental in widening the effective range of our proposed estimative equations for the preceding frequency and vibratory amplitude, further sets of field data have been collected from their in-situ measurement on six newly built r/c buildings.(2) As for damping coefficients : from reanalyzing the observed data concerned, despite their generally noted large scattering even on equally dimensioned floor slabs of the same building, a close correlation is found to exist between their mean and the average long-time deflection rati, e.g.ratio of long-time deflection to slab short span.(3) An approximate set of formulas for the long-time deflection is proposed to permit us to predict its practical amount readily from its exact culculated value ; which was derived from a parametric model analysis, using as its parameters major factors in r/c slab deflection behavior, through a standard process of the design of experiment.