Slab Vibration Model Coupled with Pier Structure on Continuous Girder Bridge

This paper proposes slab vibration model coupled with pier structure on continuous girder bridge. Vibration mode properties are expected as promising indicators in bridge health monitoring. However, there are various kinds of bridge structures depending on geographical conditions. Especially in the case of a continuous girder where an intermediate support is elastically supported by a portal pier with steel beam, vibration coupling with pier structure should be considered for modal analysis of slab vibration. Previous research of slab vibration mode without pier vibration coupling could not see whether extracted modes are physical modes or not. We proposed a slab vibration continuum model on 2-continuous-span girder with a single degree of freedom kinematic system at pier position, and estimated the vibration modes. RC-slab vibration modes were experimentally investigated on a real expressway bridge, which has 2-continuous-span steel girder where the intermediate support is elastically supported by a portal pier with steel beam. As a result, coupling vibration mode which deflected at pier position was estimated theoretically from proposed model. In experiment, the mode was observed by analyzing slab acceleration response measured at 14 points in the bridge. It is concluded that the proposed slab vibration model is effective for modal analysis, and it can be useful for bridge structural health monitoring.