$27\mathrm{.}86\mathrm{.}917$What theoretical frameworks underpin civil engineering practices, shaping infrastructure development and maintenance? From classical principles like Newton's laws of motion to modern advances in material science and computational modeling, how do these theories inform structural design, transportation systems, and environmental engineering? Consider the role of fluid dynamics in hydraulic structures, soil mechanics in foundation design, and structural analysis methods like finite element analysis. How do theories of elasticity and plasticity influence the behavior of materials under load? Additionally, explore how emerging fields such as sustainable design integrate theoretical concepts to address contemporary challenges in infrastructure resilience and environmental impact mitigation.