#$8182$ Why do civil engineers employ principles of structural mechanics in the design and construction of bridges, buildings, and other infrastructure projects? Delve into the theoretical underpinnings of structural mechanics, exploring concepts such as equilibrium, stress, and strain, as well as the behavior of materials under various loading conditions. Discuss the significance of analyzing and predicting the performance of structures to ensure their safety, reliability, and cost$-$effectiveness. Consider how advancements in computational methods and experimental techniques have enhanced our understanding of structural behavior, leading to more efficient and innovative designs. Finally, reflect on the broader implications of applying theoretical principles in civil engineering practice, including the role of sustainability, resilience, and societal impact in shaping infrastructure development.