In general, the accelerogram of earthquake and the accelerogram obtained from dynamic tests contain various errors. In these errors of the accelerogram, there are instrumental errors(magnitude and phase distortion) due to the response characteristics of accelerometer and the digitizing error concentrated in low-and high-frequency components and random errors. But these errors may have a bad effect on the results of data analysis and dynamic analysis. Therefore, more reliable analysis results can be obtained through an error correction of the accelerogram.
An efficient method which can correct the errors of the accelerogram is proposed in this study. The correction of errors can be accomplished through four steps. In the first step, using an interpolation method a data form appropriate to the error correction is prepared. In the second step, low-and high-frequency errors of the accelerogram are band-pass filtered between frequency limits prescribed. In the third step, instrumental errors are corrected using dynamic equilibrium equation of the accelerometer. In the last step, velocity and displacement are obtained by integrating corrected accelerogram.
In the proposed error correction procedure, using the properties of the differentiation and the integration of Fourier transform, the accuracy of instrument correction and integration is improved. Presently infinite impulse response(IIR) filter and finite impulse response(FIR) filter are generally used as band-pass filter. But IIR filter distorts the phase of data during filtering and FIR filter has excessive computing time during filtering. Also, both filters have the deficiencies such as the end effects and the complication of filter design. But the proposed filtering technique in frequency domain improves the deficiencies of FIR filter and IIR filter.
