Structural load

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Structural loads or actions are forces, deformations, or accelerations applied to structure components. Structural load_sentence_0

Loads cause stresses, deformations, and displacements in structures. Structural load_sentence_1

Assessment of their effects is carried out by the methods of structural analysis. Structural load_sentence_2

Excess load or overloading may cause structural failure, and hence such possibility should be either considered in the design or strictly controlled. Structural load_sentence_3

Mechanical structures, such as aircraft, satellites, rockets, space stations, ships, and submarines, have their own particular structural loads and actions. Structural load_sentence_4

Engineers often evaluate structural loads based upon published regulations, contracts, or specifications. Structural load_sentence_5

Accepted technical standards are used for acceptance testing and inspection. Structural load_sentence_6

Types Structural load_section_0

Dead loads are static forces that are relatively constant for an extended time. Structural load_sentence_7

They can be in tension or compression. Structural load_sentence_8

The term can refer to a laboratory test method or to the normal usage of a material or structure. Structural load_sentence_9

Live loads are usually variable or moving loads. Structural load_sentence_10

These can have a significant dynamic element and may involve considerations such as impact, momentum, vibration, slosh dynamics of fluids, etc. Structural load_sentence_11

An impact load is one whose time of application on a material is less than one-third of the natural period of vibration of that material. Structural load_sentence_12

Cyclic loads on a structure can lead to fatigue damage, cumulative damage, or failure. Structural load_sentence_13

These loads can be repeated loadings on a structure or can be due to vibration. Structural load_sentence_14

Loads on architectural and civil engineering structures Structural load_section_1

Structural loads are an important consideration in the design of buildings. Structural load_sentence_15

Building codes require that structures be designed and built to safely resist all actions that they are likely to face during their service life, while remaining fit for use. Structural load_sentence_16

Minimum loads or actions are specified in these building codes for types of structures, geographic locations, usage and building materials. Structural load_sentence_17

Structural loads are split into categories by their originating cause. Structural load_sentence_18

In terms of the actual load on a structure, there is no difference between dead or live loading, but the split occurs for use in safety calculations or ease of analysis on complex models. Structural load_sentence_19

To meet the requirement that design strength be higher than maximum loads, building codes prescribe that, for structural design, loads are increased by load factors. Structural load_sentence_20

These load factors are, roughly, a ratio of the theoretical design strength to the maximum load expected in service. Structural load_sentence_21

They are developed to help achieve the desired level of reliability of a structure based on probabilistic studies that take into account the load's originating cause, recurrence, distribution, and static or dynamic nature. Structural load_sentence_22

Dead load Structural load_section_2

The dead load includes loads that are relatively constant over time, including the weight of the structure itself, and immovable fixtures such as walls, plasterboard or carpet. Structural load_sentence_23

The roof is also a dead load. Structural load_sentence_24

Dead loads are also known as permanent or static loads. Structural load_sentence_25

Building materials are not dead loads until constructed in permanent position. Structural load_sentence_26

IS875(part 1)-1987 give unit weight of building materials, parts, components. Structural load_sentence_27

Live load Structural load_section_3

Live loads, or imposed loads, are temporary, of short duration, or a moving load. Structural load_sentence_28

These dynamic loads may involve considerations such as impact, momentum, vibration, slosh dynamics of fluids and material fatigue. Structural load_sentence_29

Live loads, sometimes also referred to as probabilistic loads, include all the forces that are variable within the object's normal operation cycle not including construction or environmental loads. Structural load_sentence_30

Roof and floor live loads are produced during maintenance by workers, equipment and materials, and during the life of the structure by movable objects, such as planters and people. Structural load_sentence_31

Bridge live loads are produced by vehicles traveling over the deck of the bridge. Structural load_sentence_32

Environmental loads Structural load_section_4

Environmental Loads are structural loads caused by natural forces such as wind, rain, snow, earthquake or extreme temperatures. Structural load_sentence_33

Structural load_unordered_list_0

Other loads Structural load_section_5

Engineers must also be aware of other actions that may affect a structure, such as: Structural load_sentence_34

Structural load_unordered_list_1

  • Foundation settlement or displacementStructural load_item_1_11
  • FireStructural load_item_1_12
  • CorrosionStructural load_item_1_13
  • ExplosionStructural load_item_1_14
  • Creep or shrinkageStructural load_item_1_15
  • Impact from vehicles or machinery vibrationStructural load_item_1_16
  • Construction loadsStructural load_item_1_17

Load combinations Structural load_section_6

A load combination results when more than one load type acts on the structure. Structural load_sentence_35

Building codes usually specify a variety of load combinations together with load factors (weightings) for each load type in order to ensure the safety of the structure under different maximum expected loading scenarios. Structural load_sentence_36

For example, in designing a staircase, a dead load factor may be 1.2 times the weight of the structure, and a live load factor may be 1.6 times the maximum expected live load. Structural load_sentence_37

These two "factored loads" are combined (added) to determine the "required strength" of the staircase. Structural load_sentence_38

The reason for the disparity between factors for dead load and live load, and thus the reason the loads are initially categorized as dead or live is because while it is not unreasonable to expect a large number of people ascending the staircase at once, it is less likely that the structure will experience much change in its permanent load. Structural load_sentence_39

Aircraft structural loads Structural load_section_7

For aircraft, loading is divided into two major categories: limit loads and ultimate loads. Structural load_sentence_40

Limit loads are the maximum loads a component or structure may carry safely. Structural load_sentence_41

Ultimate loads are the limit loads times a factor of 1.5 or the point beyond which the component or structure will fail. Structural load_sentence_42

Gust loads are determined statistically and are provided by an agency such as the Federal Aviation Administration. Structural load_sentence_43

Crash loads are loosely bounded by the ability of structures to survive the deceleration of a major ground . Structural load_sentence_44

Other loads that may be critical are pressure loads (for pressurized, high-altitude aircraft) and ground loads. Structural load_sentence_45

Loads on the ground can be from adverse braking or maneuvering during taxiing. Structural load_sentence_46

Aircraft are constantly subjected to cyclic loading. Structural load_sentence_47

These cyclic loads can cause metal fatigue. Structural load_sentence_48

See also Structural load_section_8

Structural load_unordered_list_2

Credits to the contents of this page go to the authors of the corresponding Wikipedia page: load.