How do the principles of structural analysis and design in civil engineering influence the decision$-$making process during the early stages of a construction project, particularly in regard to the selection of materials and structural systems? Discuss the key factors that engineers must consider, such as load$-$bearing capacity, environmental impact, sustainability, and cost$-$effectiveness, and how these factors interplay to shape the final design. Additionally, explore the role of advanced computational tools and software in aiding engineers to predict structural behavior under various conditions, and how these tools have transformed traditional practices in structural engineering.