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and plumbing (MEP) equipment, and for buildings, it's common to include a Super
Imposed Dead Load (SIDL) of around 5 pounds per square foot (psf) accounting for miscellaneous weight such as bolts and other fasteners, cabling, and various fixtures or small architectural elements. Live loads, on the other hand, can be furniture, moveable equipment, or the people themselves, and may increase beyond normal or expected amounts in some situations, so a larger factor of 1.6 attempts to quantify this extra variability. Snow will also use a maximum factor of 1.6, while lateral loads (earthquakes and wind) are defined such that a 1.0 load factor is practical. Multiple loads may be added together in different ways, such as 1.2*Dead + 1.0*Live + 1.0*Earthquake + 0.2*Snow, or 1.2*Dead + 1.6(Snow, Live(roof), OR Rain) + (1.0*Live OR 0.5*Wind).
133:
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205:(loads which are permanent and immovable excepting redesign or renovation) and wind load, as described below. In some cases structures may be subject to other loads, such as those due to earthquakes or pressures from retained material. The expected maximum magnitude of each is referred to as the characteristic load.
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The size of the load factor is based on the probability of exceeding any specified design load. Dead loads have small load factors, such as 1.2, because weight is mostly known and accounted for, such as structural members, architectural elements and finishes, large pieces of mechanical, electrical
284:
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 based on probabilistic studies that take into account the load's originating cause, recurrence, distribution, and
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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. Minimum loads or actions are specified in these building codes for types of structures, geographic locations, usage and
277:. Structural loads are split into categories by their originating cause. 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.
193:
a structure is expected to carry. These loads come in many different forms, such as people, equipment, vehicles, wind, rain, snow, earthquakes, the building materials themselves, etc. Specified loads also known as characteristic loads in many cases.
532:, 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. These two "factored loads" are combined (added) to determine the "required strength" of the staircase.
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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.
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loads a component or structure may carry safely. Ultimate loads are the limit loads times a factor of 1.5 or the point beyond which the component or structure will fail. Gust loads are determined
567:. Other loads that may be critical are pressure loads (for pressurized, high-altitude aircraft) and ground loads. Loads on the ground can be from adverse braking or maneuvering during
371:
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.
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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. These
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Imposed loads are those associated with occupation and use of the building; their magnitude is less clearly defined and is generally related to the use of the building.
528:(weightings) for each load type in order to ensure the safety of the structure under different maximum expected loading scenarios. For example, in designing a
321:. Building materials are not dead loads until constructed in permanent position. IS875(part 1)-1987 give unit weight of building materials, parts, components.
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The dead load includes loads that are relatively constant over time, including the weight of the structure itself, and immovable fixtures such as walls,
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791:
EN 1991-1-1 Euro code 1: Actions on
Structures – Part 1-1: General actions – densities, self-weight, imposed loads for buildings section 3.2
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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.
95:—are subject to their own particular structural loads and actions. Engineers often evaluate structural loads based upon published
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Environmental loads are structural loads caused by natural forces such as wind, rain, snow, earthquake or extreme temperatures.
71:, so this should be considered and controlled during the design of a structure. Particular mechanical structures—such as
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For aircraft, loading is divided into two major categories: limit loads and ultimate loads. Limit loads are the
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damage, cumulative damage, or failure. These loads can be repeated loadings on a structure or can be due to
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220:. The term can refer to a laboratory test method or to the normal usage of a material or structure.
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Buildings will be subject to loads from various sources. The principal ones can be classified as
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848:
Fisette, Paul, and the
American Wood Council. "Understanding Loads and Using Span Tables". 1997.
845:
Luebkeman, Chris H., and Donald
Petting "Lecture 17: Primary Loads". University of Oregon. 1996
819:, Volume 1, ed. I. M. Allison (Rotterdam, Netherlands: A.A. Balkema Publishers, 1998), p. 379
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67:, analyzes the effects of loads on structures and structural elements. Excess load may cause
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571:. Aircraft are constantly subjected to cyclic loading. These cyclic loads can cause
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Engineers must also be aware of other actions that may affect a structure, such as:
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Bridge live loads are produced by vehicles traveling over the deck of the bridge.
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A load combination results when more than one load type acts on the structure.
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Structural loads are an important consideration in the design of buildings.
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317:. The roof is also a dead load. Dead loads are also known as permanent or
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157: in this section. Unsourced material may be challenged and removed.
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ASCE/SEI 7-05 Minimum Design Loads for
Buildings and Other Structures
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Live loads, or imposed loads, are temporary, of short duration, or a
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that are relatively constant for an extended time. They can be in
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Mechanical loads (forces) applied to a structure or its components
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Experimental
Mechanics: Advances in Design, Testing and Analysis
832:(Cambridge; New York: Cambridge University Press, 2008), p. 129
807:(Cambridge; New York: Cambridge University Press, 2008), p. 126
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usually specify a variety of load combinations together with
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EN 1990 Euro code – Basis of structural design section 4.1.1
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738:. Bruxelles: European Committee for Standardization. 2002.
698:. Bruxelles: European Committee for Standardization. 2002.
658:. Bruxelles: European Committee for Standardization. 2002.
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633:. American Society of Civil Engineers. 2006. p. 1.
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Loads on architectural and civil engineering structures
201:(loads which are not always present in the structure),
713:. USA: International Code Council. 2000. p. 295.
189:, specified loads are the best estimate of the actual
671:Mark's Standard Handbook for Mechanical Engineers
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830:Analysis of Aircraft Structures: An Introduction
805:Analysis of Aircraft Structures: An Introduction
773:2006 International Building Code Section 1602.1.
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736:Eurocode 0: Basis of structural design EN 1990
696:Eurocode 0: Basis of structural design EN 1990
673:(10th ed.). McGraw-Hill. pp. 11–42.
656:Eurocode 0: Basis of structural design EN 1990
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505:Impact from vehicles or machinery vibration
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552:and are provided by an agency such as the
345:loads may involve considerations such as
173:Learn how and when to remove this message
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249:Cyclic loads on a structure can lead to
669:Avallone, E.A.; Baumeister, T. (eds.).
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753:. USA: McGraw-Hill. pp. 214–227.
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155:adding citations to reliable sources
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223:Live loads are usually variable or
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749:Rao, Singiresu S. (1992).
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361:of fluids and material
877:Mechanical engineering
867:Structural engineering
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450:Loads from fluids or
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872:Building engineering
828:Bruce K. Donaldson,
803:Bruce K. Donaldson,
596:Probabilistic design
439:Lateral pressure of
402:, rain and ice loads
151:improve this article
882:Structural analysis
418:changes leading to
378:Environmental loads
109:technical standards
61:Structural analysis
37:structural elements
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275:building materials
113:acceptance testing
69:structural failure
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734:"2.2.5(b)".
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694:"2.2.1(1)".
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526:load factors
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509:Construction
502:or shrinkage
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319:static loads
311:plasterboard
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282:load factors
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225:moving loads
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149:Please help
144:verification
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107:. Accepted
53:acceleration
49:displacement
24:
20:
18:
654:"1.5.3.1".
560:of a major
467:Other loads
445:groundwater
416:Temperature
339:moving load
218:compression
97:regulations
65:engineering
45:deformation
856:Categories
709:"1604.2".
617:References
479:settlement
476:Foundation
462:Dust loads
457:Permafrost
395:Wind loads
203:dead loads
199:live loads
163:April 2024
117:inspection
93:submarines
77:satellites
530:staircase
495:Explosion
490:Corrosion
355:vibration
325:Live load
305:Dead load
297:Dead load
255:vibration
237:vibration
101:contracts
57:structure
579:See also
351:momentum
341:. These
293:nature.
233:momentum
73:aircraft
569:taxiing
546:maximum
459:melting
429:Ponding
363:fatigue
343:dynamic
291:dynamic
251:fatigue
214:tension
81:rockets
757:
717:
677:
637:
565:impact
562:ground
452:floods
422:cause
347:impact
315:carpet
287:static
229:impact
91:, and
41:stress
511:loads
500:Creep
431:loads
191:loads
123:Types
103:, or
89:ships
55:in a
33:force
27:is a
755:ISBN
715:ISBN
675:ISBN
635:ISBN
485:Fire
441:soil
400:Snow
115:and
313:or
289:or
216:or
185:In
153:by
51:or
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