On the optimal sensor placement techniques for a bridge structure

Health monitoring systems set up to assure the safe operation of structures require linking sensors with computational tools able to interpret sensor data in terms of structural performance. Although intensive development continues on innovative sensor systems, there is still considerable uncertainty in deciding on the number of sensors required and their location in order to obtain adequate information on structural behaviour. aper considers the problem of locating sensors on a bridge structure with the aim of maximizing the data information so that structural dynamic behaviour can be fully characterised. Six different optimal sensor placement techniques, three based on the maximisation of the Fisher information matrix (FIM), one on the properties of the covariance matrix coefficients, and two on energetic approaches, have been investigated. Mode shape displacements were taken as the measured data set and two comparison criteria were employed. The first criterion was based on the mean square error between the FE model and the cubic spline interpolated mode shapes. The second criterion measured the information content of each sensor location to investigate on the strength of the acquired signals and their ability to withstand the noise pollution keeping intact the information relative to the structure properties. sults showed that the effective independence driving-point residue (EFI-DPR) method provides an effective method for optimal sensor placement to identify the vibration characteristics of the studied bridge. The variance method (VM) developed by the authors gave results very close to the EFI-DPR technique, in terms of the capability to capture the vibration mode shape and signal strength. However, the VM presented unique characteristics in the world of the OSP techniques, which is the indication of the optimal number of sensors (ONS).