ABSTRACT
Nonstructural elements are those systems and components attached to the floors and walls of a building or industrial facility that are not part of the main or intended load-bearing structural system for the building or industrial facility. Although not part of the main structural system, they may nevertheless also be subjected to large seismic forces and depend on their own structural characteristics to resist these seismic forces. In general, nonstructural elements may be classified into three broad categories: (1) architectural components, (2) mechanical and electrical equipment and (3) building contents. Examples of the first category are elevator penthouses, stairways, partitions, parapets, heliports, cladding systems, signboards, lighting systems and suspended ceilings. Some of the second are storage tanks, pressure vessels, piping systems, ducts, escalators, smokestacks, antennas, cranes, radars and object tracking devices, computer and data acquisition systems, control panels, transformers, switchgears, emergency power systems, fire protection systems, boilers, heat exchangers, chillers, cooling towers and machinery such as pumps, turbines, generators, engines and motors. Among some of those in the third category are bookshelves, file cabinets, storage racks, decorative items and any other piece of furniture commonly
found in office buildings and warehouses. Alternative names by which these elements are also known are “appendages,” “nonstructural components,” “building attachments,” “architectural, mechanical, and electrical elements,” “secondary systems,” “secondary structural elements” and “secondary structures.” The name that best describes their nature is secondary structures, since it reflects the fact that they are not part of the main structure but must possess, nevertheless, structural properties to maintain their own integrity.
