System reliability for bridge evaluation

System reliability can be used as an important tool in the efficient evaluation of existing structures. The traditional approach is based on the consideration of individual components rather than structures. Consequently, the acceptance criteria are formulated in terms of the allowable stress, or ultimate moment, in a component. However, it has been observed that the load carrying capacity of the whole structure (system) is often much larger than what is determined by the design of components. The difference can be attributed to the system behavior. Quantification of this difference is the subject of the system reliability. This paper deals with calculation of the reliability of the whole bridge structure, taking into account realistic boundary conditions, and site-specific load and resistance parameters. The objective is to compare the reliability of components and whole system for girder bridges. The reliability analysis is performed for main girders and sensitivity analysis is performed for load and resistance parameters while the focus is on the differences between the reliabilities calculated for components and structural systems.

• Introduction

• System Reliability Model for Girder Bridges

• Bridge Load Model

• Resistance Model

• Reliability Analysis for Selected Bridges

• Sensitivity Analysis

• Conclusions

• Acknowledgments

• References