Structural optimization is essential for designing efficient and cost$-$effective structures by optimizing their geometry, material distribution, and structural configuration. Construct a theoretical framework elucidating the principles of structural optimization, including mathematical optimization techniques like linear programming, genetic algorithms, and finite element methods. Discuss theoretical models for form$-$finding and topology optimization, and explore theoretical approaches to optimizing structural performance criteria, such as stiffness, strength, and stability. Analyze the implications of structural optimization for enhancing sustainability, resilience, and innovation in civil engineering design practice.