QUICK EARTHQUAKE DAMAGE EVALUATION METHOD FOR RC PIERS USING ACCELERATION MEASUREMENTS

Abstract

This study proposed a quick earthquake damage evaluation method for RC piers using the short-time transfer function (STTF) obtained from acceleration measurements. This research aims to confirm whether the damage occurrence can be detected from the STTF and the damage degree (maximum displacement) can be estimated from the predominant frequency of the STTF. First, the method was applied to the shaking table test results. The predominant frequency decreased when the crack of concrete or the yielding of the reinforcing bar occurred. Therefore, it was confirmed that the damage occurrence could be detected as the reduction of the predominant frequency. The lowest predominant frequency during excitation was sensitive to the maximum displacement, while the predominant frequency at the end of the exaction was not sensitive to the maximum displacement.The method was also applied to the numerical analysis results. In conclusion, it was confirmed that the method could detect damage occurrence, damage progress, and non-occurrence of damage progress from the transition of the predominant frequency. Also, it was found that the maximum displacement is proportional to the square of the ratio of the initial predominant frequency to the lowest predominant frequency. The possibility to estimate the maximum displacement from the lowest predominant frequency was illustrated.