Optimum Sensor Placement Method for Cable-Stayed Bridges Based on Damage Identifiability

In order to make the modal parameters identified by the sensors on cable-stayed bridges that are sufficiently sensitive to structural damage, a damage information index of the node degree of freedom containing the damage information of all elements was proposed and obtained, considering the damage identifiability requirements for optimum sensor placement, and using the method of parameter study and parameter correlation theory. The damage information regarding the degrees of freedom of the nodes could be ordered by ranking the index, i.e. by ranking the damage sensitivity of each degree of freedom. This process did not require the use of any optimization iterative algorithm. Based on this proposal, the first such method for optimum sensor placement, which can avoid defects such as inefficient iterations and optimization, could be analysed. Finally, the location of the sensor, which could provide satisfactory damage identifiability and modal observability, was obtained. The feasibility of the proposed method was demonstrated using a single-tower double-cable-plane cable-stayed bridge. A comparison of the results with those obtained using the EI method (effective independence method) revealed that the total damage information obtained using the proposed method is greater by factors of 589, 582, and 591 for the 3rd, 4th, and 5th orders, respectively.