What fundamental principles underpin the structural analysis and design methodologies in civil engineering, encompassing considerations of material behavior, structural mechanics, and environmental loads? How do these principles guide the development of resilient and sustainable infrastructure systems, particularly in mitigating risks posed by natural hazards and ensuring long$-$term structural integrity? Furthermore, how do advancements in computational techniques and materials science contribute to the evolution of design practices aimed at optimizing structural performance while meeting societal needs for safety, functionality, and economic feasibility?