In civil engineering, foundational theories underpin structural design, material behavior, and fluid mechanics. Structural engineering relies on principles of statics and mechanics of materials to ensure structural integrity and stability. Material science contributes to understanding material properties and durability, crucial for infrastructure longevity. Fluid mechanics governs fluid behavior in hydraulic systems, such as water flow in pipelines and open channels. Geotechnical engineering focuses on soil mechanics and foundation design, crucial for supporting structures. Transportation engineering considers traffic flow theory and infrastructure design for efficient transportation networks. These theories form the basis for designing safe, resilient, and sustainable civil infrastructure.