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This study investigated a number of different damage detection algorithms for structural health monitoring of a typical cable-stayed bridge. The Bayview Bridge, a cable-stayed bridge in Quincy, Illinois, was selected for the study. The focus was in comparing the viability of simplified techniques for practical applications. Accordingly, the numerical analysis involved development of a precise linear elastic finite element model (FEM) to simulate various structural health monitoring test scenarios with accelerometers. The Effective Independence Method was employed to locate the best distribution of the accelerometers along the length of the bridge. The simulated accelerometer data based on the FEM analysis was employed for the evaluation of the four damage identification methods investigated here. These methods included the Enhanced Coordinate Modal Assurance Criterion, Damage Index Method, Mode Shape Curvature Method, and Modal Flexibility Index Method. Some of these methods had been previously applied only to a number of specific bridges. However, the investigation here provides the relative merits and shortcomings of the damage detection methods in long-span cable-stayed bridges.

Condition Monitoring of civil structures is best accomplished by way of distributed sensors. Sensors capable of making distributed measurements allow for monitoring the entire structure. Optical fiber sensors are especially very attractive for this purpose, since they are geometrically versatile and they can be readily integrated within various types of structures and materials. The research presented here describes the development of a new optical fiber sensor system for measurement of structural strains based on white light interferometry. Individual sensors are linked in series and an optical switch provides for multiplexing of strain signals from various locations in the structure. Bragg grating type fiber optic sensors as well as strain gauges were employed for comparison and verification of strain signals as measured by the new system. The system provides capability for distributed sensing of strains in large structures.