Bridge ManagmentBridge Management Systems (BMS) are tools to store, organize, and manipulate data relavent to the serviceability and safety of the bridges. Existing BMS are efficient in storing data and prioritizing bridges in need of maintenance and rehabilitation with regard to the available budgets. However, they are only as good as the models used in analysis. BMS need routine implementation of new technologies, which will give bridge inspectors and engineers the necessary information to determine an appropriate repair and rehabilitation action.
Prediction models are used in BMS to track trends in component and system deterioration. Improved prediction models can lead to improved reliability of the results from BMS. To allocate funds properly, a reliable and consistent BMS that will keep bridges in safe and serviceable conditions while keeping maintenance cost within the available budget is essential.
Deterioration ModelsDeterioration models describe the slow degradation and change in strength of a material. Material deterioration leads to reduced member performance, reduced structural performance, and ultimately reduced reliability of a structural system. The models relate the causes of deterioration to its mechanisms, and outcomes such as change in cross-sectional area member strength, and structural load rating.
Deterioration models are used to predict the change in structural parameters due to the intended structural loading, environmental conditions, maintenance practices, and historical data. The degradation at both the system and component level is based on time-dependent deterioration models that relate the structure system to the environment. Thus, deterioration models are fundamental considerations in the development of prediction models for bridge performance or condition. Practically, deterioration models can be used to correlate service environment and service life to optimal maintenance scheduling and life-cycle analysis.
ReliabilityStructural reliability is the probability that a structure will perform its function within pre-specified limits. It is more and more important to make efficient use of resources due to the seriousness of infrastucture deterioration and scarce financial resources. In order to solve the problems in highway bridge engineering, and to keep a balance between structural safety and economy, structural reliability concepts are needed. Two reliability indices are of interest in the case of civil infrastructure systems: (1) an index that measures the failure probability for a structure when subjected to a damaging event; and (2) an index that measures serviceability probability.
The purpose of our research is to apply reliability concepts to highway bridge engineering and to put them into use with structural ID, deterioration models, prediction models, and bridge management.
Performance PredictionPerformance based prediction models for bridge deterioration enhances the information currently available to the decision makers and BMS. The prediction models track time and can be based on the mixed quantitative and qualitative information obtained in the field. By using case histories developed for individual bridges and isolating parameters that relate specific causes to bridge deterioration, it is possible to generalize the models to a set of parameters which consider bridge type, use, and environmental conditions.
For maintenance and rehabilitation activities for any infrastructure system, the information on the current state and potential future infrastructure condition is essential. Decisions about a structure's safety and maintenance needs are made based the mixed information obtained in the field. By collecting data on a regular basis it is possible to identify trends and predict future condition states.
Structural IdentificationStructural identification is the process of developing an analytical model of a structure such that for a given set of inputs the model can simulate the output response. Structural parameter estimation, one area within the field of structural identification uses optimization to reconcile an analytical model of a structure with full-scale test data. The result is a set of estimated parameters (modal or stiffness properties) capable of simulating "actual" structural response. Structural identification is an objective tool for condition assessment of structures the current application is bridge condition assessment. By using structural identification and parameter estimation as a means of determining the actual state properties, performance, and limit states of a structure it is possible to gain an improved understanding of a structure's capacity and typical performance during serviceability. Thus, at any point in time it would be possible to assess the reliability of the structure using the objective results obtained through structural identification.