$555$ ## What are the theoretical foundations that underpin civil engineering practices, encompassing principles of structural mechanics, materials science, geotechnical engineering, and fluid dynamics? How do these theoretical frameworks influence the design, construction, and maintenance of infrastructure projects such as buildings, bridges, dams, and highways? Furthermore, how do advancements in theoretical understanding contribute to innovations in civil engineering, including the development of sustainable and resilient infrastructure solutions to address contemporary challenges such as climate change and urbanization?