Long-term Structural Health Monitoring of Short- and Medium- Span Reinforced Concrete Bridges

Description

Since the collapse of the I-35W Mississippi River bridge on August 1, 2007, many engineers have recognized the importance of structural health monitoring (SHM). With the advances in sensor and data acquisition technologies, it is now possible to obtain a set of reliable dynamic measurements. However, the extraction of useful information from this set of measurements for structural model updating and damage detection remains a challenging area of research. A key difficulty is the selection of a “suitable” class of models. It is well known that the model parameter identification process is uncertain in nature due to the problems of modeling error, measurement noise, and “incomplete” measurement. If the model class selected is too complicated (i.e., has too many model parameters), then the results of model identification will become unidentifiable. However, if the model class adopted is too simple, then the prediction error will be very large, thus resulting in unreliable identification results. Rather than assume a single model class in the identification process, the method used in the proposed study will follow a multiple model-class approach that considers all “plausible” model classes in this process and weighs their relative importance through the Bayesian probabilistic approach.It would be impractical to develop a general damage-detection method applicable to all types of structural systems (e.g., bridges, buildings, and towers) with any structural form (e.g., frames and trusses), construction materials (e.g., reinforced concrete, steel, or composite), and types of damage (e.g., material degradation, the formation of plastic joints, and the buckling of structural members). To develop a robust and efficient damage-detection method for real structures, the characteristics of the target structure and the damage type must be considered in the development stage. It is the main objective of the proposed project to put forward an SHM methodology that is specifically designed for reinforced concrete bridges in Hong Kong. The Highways Department (HyD) currently maintains more than 1000 reinforced concrete bridges in Hong Kong. The proposed methodology is thus extremely important for ensuring their structural safety.