Delve into the principles of structural reliability and risk analysis in civil engineering, exploring probabilistic methods and mathematical models used to quantify the likelihood of structural failure under various loading and environmental conditions. Discuss the role of uncertainties in material properties, loading parameters, and structural behavior in influencing reliability assessments, and elucidate the concepts of failure probability, safety factors, and risk metrics in evaluating structural performance against predefined safety criteria. Furthermore, examine the application of reliability$-$based design approaches and risk$-$informed decision$-$making strategies in enhancing the robustness and resilience of civil infrastructure systems, considering factors such as life$-$cycle cost optimization, societal risk tolerance, and sustainability objectives.