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通过环境振动测量,估算了大量现存建筑物平移运动的基频和相对阻尼。文中第一部分主要用以下4种不同的方法比较了脉动与地震记录的测量结果:水平分量与竖向分量的频谱比、标准频谱比、非参数阻尼分析(NonPaDAn)和半带宽方法。将一对加速度计分别置于一栋5层钢筋混凝土(RC)建筑的底层和顶层以记录局部地震数据,然后收集了加速度计在同一位置上的脉动测量数据。脉动与地震记录测量结果一致,使我们有信心将环境噪声测量方法推广到大量建筑物上。用上述方法对数据进行分析得到了意大利波坦察和塞尼加利亚城区内80栋建筑物在正交方向上2个主要的平移运动频率和相对阻尼值。由不同方法得到的频率值符合得很好。但对阻尼的估算目前还没有得到同样满意的结果:非参数阻尼分析提供的估算值离散小,聚合程度好,似更符合实际。最后,将实测频率与其他实验结果和理论模型进行了比较。与前人已报道的观点一致,我们的结果进一步证实,理论上的周期—高度关系高估了实验数据。
Through the measurement of environmental vibration, the fundamental frequency and relative damping of a large number of existing buildings are estimated. In the first part of the paper, the measurement results of pulsations and seismograms are compared mainly by the following four different methods: spectral ratio of horizontal component and vertical component, standard spectral ratio, non-parametric damping analysis (NonPaDAn) and half-bandwidth method. A pair of accelerometers were placed on the bottom and top of a five-story reinforced concrete (RC) building to record local seismic data and then collected pulsatile measurements of the accelerometer at the same location. Fluctuations coincide with seismogram measurements, giving us the confidence to extend the measurement of ambient noise to a large number of buildings. Using the above method to analyze the data, two major translational movement frequencies and relative damping values in the orthogonal direction of 80 buildings in the urban areas of Potenza and Senigallia, Italy were obtained. The frequency values obtained by different methods are in good agreement. However, the same satisfactory results have not yet been obtained in the estimation of damping: the non-parametric damping analysis provides a small discretization and a good degree of polymerization, which is more realistic. Finally, the measured frequency is compared with other experimental results and theoretical models. In line with what has been reported previously, our results further confirm that the theoretical cycle-height relationship overestimates the experimental data.