What are the fundamental principles behind structural analysis methods in civil engineering, and how do engineers apply them to ensure the safety and stability of various structures? How do soil mechanics principles influence the design and construction of foundations, and what factors do civil engineers consider when selecting the appropriate foundation type for different soil conditions? How does fluid mechanics play a role in hydraulic engineering projects, and what are the key parameters that engineers must analyze to design efficient and sustainable water distribution systems? How do transportation engineers optimize traffic flow and safety through the application of traffic engineering principles, and what strategies are employed to mitigate congestion and improve overall transportation network performance?