Optimal sensor placement on cables of cable-stayed bridges for structural damage evaluation

Recently, a new static-based method using the measured changes in cable forces to identify structural damage in deck girders of cable-stayed bridges has been developed by the authors. The cable forces can be measured with high precision if done properly, but it is impractical to install sensors on all the cables of a bridge. The amount of structural damage information obtained from the incomplete measurement of cable forces is largely dependent on the sensor layout. In this paper, an optimal sensor placement (OSP) method targeting structural damage evaluation for cable-stayed bridges from the measurement of cable forces is proposed to determine the optimal sensor configuration on cables so that the amount of damage information inherent in the measurement data is maximized. A damage information index (Dil), which measures the damage information contained in the measured cable forces and their changes, is defined based on the cable force sensitivity matrix and adopted as an optimality criterion for the OSP. The optimal sensor locations are expanded iteratively to include the cables which offer the greatest increase in the Dil until the required number of sensors is achieved. The cable-stayed Sutong Bridge is utilized to validate the effectiveness of the proposed method.