$156$y What are the core theoretical principles that underlie civil engineering? Specifically, how do principles such as structural analysis, soil mechanics, fluid dynamics, and transportation theory provide the theoretical foundation for designing and constructing infrastructure projects? Additionally, how do civil engineers apply these theories to address challenges in urban development, environmental sustainability, and disaster resilience? Furthermore, how do advancements in materials science, computational modeling, and sustainable design principles contribute to the evolution of civil engineering theory and practice?