Changes in the Dynamic Characteristics of a Small-Scale Gymnasium Model Due to Simulated Earthquake Damage

Abstract

In this study, the authors used shake-table tests to assess the modal parameters of a small-scale gymnasium model with simulated damage, the feasibility of estimating the damage to large-span building structures was studied. In Japan, large-span structures, such as gymnasiums, are expected to be used as evacuation shelters when a natural disaster occurs. As the shelter itself may be damaged in case of an earthquake, it is critical to determine whether damage has occurred, where it occurred, and how serious it is, before the shelter is used. The small-scale gymnasium was designed based on the similarity rule. Observed earthquake ground motions scaled to aftershock levels were applied to the model. The natural frequencies and mode shapes were obtained from the measured response accelerations. To study the influence of structural damage on the modal parameters, a gymnasium model with simulated damage was also tested. The results indicate that the modal parameters, e.g., natural frequencies and mode shapes, can be obtained from the response accelerations, and the damage patterns can be estimated from the changes in these modal parameters.