Dynamic Characteristics Identification for an Arch Bridge Using Wireless Sensor Networks before and after Seismic Retrofit; the Application to Model Updating

Functionalities of wireless sensors to measure bridge dynamic behavior are maturing; dense measurements of large structures are expected to reveal details of the behavior of existing structures. Traffic-induced vibrations at an arch bridge, instrumented by 48 wireless smart sensors, were measured before and after seismic retrofit of the structure. The differences between the measured dynamic characteristics represent the effects of seismic retrofit. A comparison of mode shapes reveals their changes, which are then used to update the finite element model of the bridge; densely measured mode shapes are also shown to be sensitive to structural changes. A potential use of dense instrumentation has been demonstrated.