Finite Element Modelling and High-Level Statistical Analysis for Bridge Condition Prediction and Management

Abstract

Efficient management strategies are essential to ensure bridge safety and functionality while accommodating budget limitations. For such purpose, bridge management systems (BMSs) developed policies to predict the global bridge conditions and any performance deficiencies in the individual components. However, the current policies have some shortcomings that may limit their efficiencies. To address these shortcomings, this thesis proposes several enhancements to three major BMS policies covering inspection and maintenance planning, bearing performance assessment, and seismic screening. Inspection and maintenance are often planned using Markov Chains deterioration models derived from past inspection records. However, Markov Chains models employ impractical assumptions and neglect the subjectivity of inspections. Alternatively, parameterized fuzzy-logistic deterioration models are proposed to predict future conditions given easy-to-track parameters, such as age and last maintenance date. The proposed models can yield better maintenance predictions compared to Markov Chains and can reduce inspection costs by 30%. Bearing performance assessment policies are limited to testing bearing material or its behaviour at design displacements. In practice, bearings experience fatigue with repeated displacement cycles even if at low magnitudes, leading to bearing degradation and long-term increase in demands. Thus, a parameterized loading protocol is proposed to guide laboratory testing in assessing the fatigue life. The protocol is derived from the bearing demands attributes observed from a 3D nonlinear analysis in OpenSees for various bridge configurations and loading conditions. Seismic screening policies were developed to identify the most vulnerable bridges, giving them the highest priorities. The current policies are qualitative, relying on identifying vulnerable details, rather than quantifying the actual performance. Furthermore, the vulnerability estimates are not updated with deterioration. Thus, new risk-based screening procedures are proposed via fragility analysis of the critical components, bearings and columns, while considering their deterioration. Given the components’ fragilities, a seismic vulnerability index is computed to rank the bridge’s priority.