A Structural Engineer analyzes and designs the gravity support and lateral force resistance of buildings, bridges, and other structures.
This is the person whose responsibilities we are defining. Structural Engineering is a specialty within Civil Engineering. Structural Engineers create drawings and specifications, perform calculations, review the work of other engineers, write reports and evaluations, and observe construction sites. A Professional Engineer’slicense is required in order to practice Structural Engineering. A license can be obtained only after completing a prescribed amount of education and work experience, and taking a 2-day exam. In California and other states, certain structures, such as hospitals and schools, require a Structural Engineer’s license, which can be obtained after 3 years additional experience and taking another exam.
The basic tasks of structural engineering relate numerical quantities of physical forces to physical configurations of force-resisting elements. Analysis is the process of determining forces in each element in a structure (such as a beam) when the configuration of elements is already defined. Design is the process of configuring elements to resist forces whose values are already known. Analysis and Design are complementary procedures in the overall process of designing new structures. After performing a preliminary design, the designer estimates the final configuration of elements of a structure, but only until an analysis is performed can the forces in those elements be known. After performing an analysis, the element forces are known, and the elements can be designed (their configuration can be chosen) more precisely. The process iterates between analysis and design until convergence is achieved.
Structures are subject to vertical, or "Gravity" Loads and horizontal, or "Lateral" Loads. Gravity loads include "dead", or permanent, load, which is the weight of the structure, including its walls, floors, finishes, and mechanical systems, and "live", or temporary load, which is the weight of a structure's contents and occupants, including the weight of snow. Lateral loads include those generated by the wind, earthquakes, or explosions. Structural elements must be designed so that, as a system, the structure can resist all loads that will act upon it.
Structures are any system that resists vertical or horizontal loads. Structures include large items such as skyscrapers, bridges, and dams, as well as small items such as bookshelves, chairs, and windows. Most everyday "structures" are "designed" by testing, or trial and error; while large, unique, or expensive structures that are not easily tested are generally designed by a qualified structural engineer using mathematical calculations. Most practicing structural engineers design and analyze buildings, bridges, power plants, electrical towers, dams, and other large structures that are essential to life as we know it.