The process of designing and analyzing structures is a comprehensive journey that begins with a specific need from a client. For instance, envision a scenario where an engineering or architectural firm is tasked with creating plans for a sports complex. This complex must not only accommodate a regulation football field but also cater to 60,000 spectators, provide parking for 4000 cars, and allocate space for essential facilities. Another example could involve a city hiring an engineer to design a bridge spanning a wide river, capable of handling a specific volume of traffic.
The initial phase involves conceptual design, where all potential layouts and structural systems are explored to meet project requirements. Collaboration between architects and engineers is common at this stage to ensure both efficient structural systems and alignment with architectural needs. Preliminary sketches, primarily of an architectural nature, outline the main structural elements while leaving structural details somewhat open.
In the preliminary design phase, the engineer identifies promising structural systems from the conceptual designs and sizes their main components. This step demands an understanding of structural behavior and an awareness of potential loading conditions. Rough computations are made to estimate proportions, guiding the engineer in selecting the most viable designs.
Despite not having exact member sizes and architectural details, an analysis of structural systems is conducted using estimated load values. This reveals forces at critical sections and deflections influencing the structure’s serviceability. While the true weight of members and architectural details remain in flux, experienced designers leverage past knowledge to make close approximations.
Results from the preliminary design analysis lead to a recomputation of the proportions of main elements. Even with estimated loads, the forces identified are indicative of the structure’s capacity, minimizing the need for significant changes during the final design phase.
Various preliminary designs undergo comparison based on factors like cost, material availability, appearance, maintenance, and construction time. The design that best aligns with client criteria is chosen for further refinement in the final design phase.
In the final design phase, minor adjustments are made to enhance the selected structure’s economy or appearance. Rigorous analysis evaluates strength and stiffness for significant loads and combinations. If deficiencies arise, the designer may modify the structure’s configuration or explore alternate systems.
Materials like steel, reinforced concrete, wood, and metals are analyzed similarly. Each material’s unique properties are considered, referencing design codes during sizing. While design and analysis are usually distinct courses in engineering programs, their close interrelation prompts a touch upon design issues within this discussion.