task $99===$What theoretical frameworks in civil engineering underpin the analysis and design of structures, infrastructure, and urban systems? Explore the foundational principles such as structural mechanics, materials science, fluid dynamics, and geotechnical engineering. Discuss how these theories inform decision$-$making processes in construction projects, including risk assessment, sustainability considerations, and resilience planning. Additionally, delve into the application of mathematical models, computational methods, and empirical research to validate and refine theoretical constructs. How do these theories adapt to evolving challenges like climate change, population growth, and technological advancements, ensuring the safety, efficiency, and longevity of civil engineering projects?