Empirical formula for fundamental vibration periods of reinforced concretebuildings in Taiwan

More than 30 buildings around Taiwan have been selected to monitor the floo r responses under seismic excitation. The structural array monitoring syste m in each building controls at most 27 channels of accelerometers distribut ed in several floors. Those buildings were triggered by many events during the past five years of operation. In each building, the records at the base ment can be considered as the ground excitation, and the others at the uppe r floors are the structural responses. The frequency transfer functions of those buildings can be identified by ARX models, and then the fundamental v ibration periods are estimated. The identified fundamental vibration period s using different events are compared in order to ensure the reliability of system identification. An empirical formula in predicting the fundamental vibration period is presented through the regression analysis to the identi fied fundamental vibration periods of 21 reinforced concrete (RC) moment-re sisting frame (MRF) buildings. It is found that the height of a building pl ays an important role in predicting the fundamental vibration period, compa red with the length, width, and time after completion of the building. It i s also found that the RC MRF buildings in Taiwan tend to be stiffer than th ose in the U.S. Copyright (C) 2000 John Wiley & Sons, Ltd.