Question: In civil engineering, the theory of elasticity is fundamental for understanding the behavior of structural materials under load. Explain how the theory of elasticity informs the design and analysis of bridges, focusing on the concept of stress, strain, and their relationship to material properties. Discuss the significance of considering elasticity in structural engineering, highlighting its role in ensuring the safety, durability, and efficiency of civil infrastructure projects. Provide examples of how engineers apply elasticity theory in practical design scenarios, illustrating its importance in achieving optimal structural performance and longevity.