It is important for a structural engineer to recognize the various types of elements composing a structure and to be able to classify structures as to their form and function.We will introduce some of these aspects now and expand on them at appropriate points throughout the text.
- Once the dimensional requirements for a structure have been defined, it becomes necessary to determine the loads the structure must support.
- Often, it is the anticipation of the various loads that will be imposed on the structure that provides the basic type of structure that will be chosen for design. For example, high-rise structures must endure large lateral loadings caused by wind, and so shear walls and tubular frame systems are selected, whereas buildings located in areas prone to earthquakes must be designed having ductile frames and connections.
- Once the structural form has been determined, the actual design begins with those elements that are subjected to the primary loads the structure is intended to carry, and proceeds in sequence to the various supporting members until the foundation is reached.
- Thus, a building floor slab would be designed first, followed by the supporting beams, columns, and last, the foundation footings. In order to design a structure, it is therefore necessary to first specify the loads that act on it.
- The design loading for a structure is often specified in codes. In general, the structural engineer works with two types of codes: general building codes and design codes.General building codes specify the requirements of governmental bodies for minimum design loads on structures and minimum standards for construction.
- Design codes provide detailed technical standards and are used to establish the requirements for the actual structural design.
- It should be realized, however, that codes provide only a general guide for design. The ultimate responsibility for the design lies with the structural engineer.