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

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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.