Structural engineers are specialists in design, construction, repair, conversion, and conservation. They are concerned with all aspects of a structure and its stability and safety. Structural engineering is considered a subspecialty of civil engineering.
Structural engineers are a key part of the design and construction team, working alongside other engineering disciplines to create all kinds of structures, from houses, theaters, sports stadiums, and hospitals, to bridges, oil rigs, and space satellites. They also consider the aesthetics of the site and the community in which it will be built.
Every structure must be built with consideration of the conditions of the its location. Bridges in cold, snowy climates will need to be built with continuous snow and ice loads in mind. Bridges need to carry different kinds of loads, be it people, cars, or high-speed trains. It is a structural engineer’s job to consider all the possible factors, such as dead load (the weight of the structure) and dynamic load (loads that can change or are applied with motion). The structures have to be stiff enough so they do not exceed the vibration limits for which they were designed.
Fatigue (the tendency of material to break under repeated stress) and torsion are also important factors to consider when deciding the materials best suited to a bridge design, taking into account the durability of the materials and possible causes of deterioration.