Optimal Sensor Placement for Stay Cable Damage Identification of Cable-Stayed Bridge under Uncertainty

Large cable-stayed bridges utilize hundreds of stay cables. Thus, placing a sensor on every stay cable of bridges for stay cable damage identification (SCDI) is costly and, in most cases, not necessary. Optimal sensor placement is a significant and critical issue for SCDI. This paper proposes the criteria for sensor quantity and location optimization for SCDI on the basis of the concept of damage identification reliability index (DIRI) under uncertainty. Random elimination (RE) algorithm and heuristic random elimination (HRE) algorithm are proposed to solve the sensor quantity optimization calculation problem. Multistage global optimization (MGO) algorithm is also proposed to solve the sensor location optimization calculation problem. A case study is conducted to evaluate and verify the criteria and algorithms. Results indicate that the HRE algorithm can provide better solution with less elapsed time than the RE algorithm can in some cases, and the MGO algorithm can meet the multistage criterion for sensor location optimization and give a satisfying optimized solution. Theoretical analysis and case study results confirm that the criteria are reasonable and suitable for optimal sensor placement for SCDI. The proposed algorithms are effective and efficient for practical optimization calculation. 1. Introduction In recent years, bridge health monitoring system (BHMS) has been developed rapidly and widely used in large bridges, especially in cable-stayed bridges. Sensors, which are required to monitor the structural status and influential environmental parameters, are the most important foundation of BHMS. Since the project budget of BHMS is always limited, how to optimally place the limited sensors in a large bridge in order to obtain the best data for parameter and damage identification is a challenging task. Research activities in the last few years have been focused on the design and optimization of sensor placement. Some latest representative studies are presented as follows. Kim et al. [1–3] presented a design of autonomous smart sensor nodes to monitor tendons and girders in prestressed concrete (PSC) bridges and a design of hybrid acceleration-impedance sensor nodes on Imote2-platform for damage monitoring in steel girder connections. Ho et al. [4] presented a type of solar-powered, multiscale, vibration-impedance sensor node on Imote2 platform for hybrid structural health monitoring (SHM) in cable-stayed bridge. Yi et al. [5] attempted to explore the sensitive range of the Fiber Bragg Grating (FBG) sensor and proposed an optimal placement for FBG