Search results
Results From The WOW.Com Content Network
In engineering, a factor of safety (FoS) or safety factor (SF) expresses how much stronger a system is than it needs to be for an intended load.Safety factors are often calculated using detailed analysis because comprehensive testing is impractical on many projects, such as bridges and buildings, but the structure's ability to carry a load must be determined to a reasonable accuracy.
These load factors are, roughly, a ratio of the theoretical design strength to the maximum load expected in service. They are developed to help achieve the desired level of reliability of a structure [ 6 ] based on probabilistic studies that take into account the load's originating cause, recurrence, distribution, and static or dynamic nature.
A factor of safety is a design criteria that an engineered component or structure must achieve. = /, where FS: the factor of safety, Rf The applied stress, and F: ultimate allowable stress (psi or MPa) [13] Margin of Safety is the common method for design criteria. It is defined MS = P u /P − 1.
Limit State Design (LSD), also known as Load And Resistance Factor Design (LRFD), refers to a design method used in structural engineering. A limit state is a condition of a structure beyond which it no longer fulfills the relevant design criteria. [ 1 ]
1.0 x Dead Load + 1.0 x Live Load. Different load cases would be used for different loading conditions. For example, in the case of design for fire a load case of 1.0 x Dead Load + 0.8 x Live Load may be used, as it is reasonable to assume everyone has left the building if there is a fire.
The structural designs are integrated with those of other designers such as architects and building services engineer and often supervise the construction of projects by contractors on site. [2] They can also be involved in the design of machinery, medical equipment, and vehicles where structural integrity affects functioning and safety.
A dynamic load can have a significantly larger effect than a static load of the same magnitude due to the structure's inability to respond quickly to the loading (by deflecting). The increase in the effect of a dynamic load is given by the dynamic amplification factor (DAF) or dynamic load factor (DLF):
When the load factor is greater than +1 all occupants feel heavier than usual. For example, in a 2 g maneuver all occupants feel that their weight is twice normal. When the load factor is zero, or very small, all occupants feel weightless. [2]: 398 When the load factor is negative, all occupants feel that they are upside down.