Abstract
It is common knowledge that damping properties are important in evaluating safety of structures or running safety of railway vehicles during earthquake. For instance, it is pointed out that the differences of damping constant of railway structures may have caused the different damages of structures in recent earthquakes. That's the reason why it is very important to evaluate damping properties for extracting such railway structures as to attract special attention in seismic assessment. However, there is no adequate evaluation method of damping properties at present because there are only a few measurement examples for damping properties and the occurrence factors of damping are very complex. In this study, we measured damping constants of railway viaducts of various structural types and in various ground conditions by using two vibration measurement methods named impact vibration examination and microtremor measurement. As a result, we can notice that the ratio of the structural period to the ground's ones is correlated to the damping constant, and we propose the evaluation method of damping constants of railway viaducts. Furthermore, we propose the extraction method of low damping viaducts regarding running safety by applying the proposed evaluation method.
