What Does Dead Load Mean?
A dead load is a load (weight) that doesn’t change significantly over time. The concept is applied to permanent, fixed-place equipment, as well as fittings that integrate into the structure (e.g. plumbing), non-structural elements (e.g. floor and ceiling material) and permanent, structural components of the building (e.g. slabs, beams, and columns).
Occupational safety authorities use the concept of dead load when they investigate workplace building collapses, as well as in definitions of the minimum load-bearing requirements for temporary structures used in construction, such as scaffolding.
Safeopedia Explains Dead Load
In some approaches to building design, only structural components are referred to as dead load, while non-structural and fixed-place (semi-permanent) elements of the building are often referred to as superimposed dead load. Other design standards and some building codes refer to all of these elements collectively as dead load and do not distinguish between them.
The concept of dead load can also be referred to as “self load,” which means rather than referring to weight placed upon the structure, it refers to the weight of the structure itself. As dead load, it can be contrasted against the concept of “live load” (working load), which refers to all the elements of the building that cause fluctuations in the magnitude and location of weight borne by the structure. Live elements include workers, materials, and tools.
Building and occupational safety standards often require that a structure must support an amount of weight in terms that refer to the structure's dead load. This type of reference is called a "dead load safety factor." For example, the California Code of Regulations section 1637 requires that all scaffolds built for construction projects be able to support their own weight (their dead load) plus four times the maximum intended live load.
Load is generally phrased in terms of load per unit area, such as pounds per square foot. The concepts of dead load and live load are used to allow engineers and other qualified persons to effectively categorize the various load patterns that are placed upon a particular structure. Construction projects with a safety element related to dead load often require a recognized qualified person to certify their safety, such as an engineer certified by the American Society of Civil Engineers.