text:
Sahel
From Wikipedia, the free encyclopedia
Jump to: navigation, search
For other uses, see Sahel (disambiguation).
The Sahel region in Africa: a belt up to 1,000 km (620 mi) wide that spans the 5,400 km (3,360 mi) from the Atlantic Ocean to the Red Sea
The Sahel (/səˈhɛl/)[1] is the ecoclimatic and biogeographic zone of transition in Africa between the Sahara to the north and the Sudanian Savanna to the south. Having a semi-arid climate, it stretches across the south-central latitudes of Northern Africa between the Atlantic Ocean and the Red Sea. The name is derived from the Arabic word sāḥil (ساحل, Arabic pronunciation: [ˈsaːħil]) meaning "coast" or "shore" in a figurative sense (in reference to the southern edge of the vast Sahara),[2][3] while the name Swahili means "coastal [dweller]" in a literal sense.
The Sahel part of Africa includes (from west to east) parts of northern Senegal, southern Mauritania, central Mali, northern Burkina Faso, the extreme south of Algeria, Niger, the extreme north of Nigeria, central Chad, central and southern Sudan, the extreme north of South Sudan, Eritrea, Cameroon, Central African Republic and extreme north of Ethiopia.[4]
Historically, the western part of the Sahel was sometimes known as the Sudan region.[5] This belt was roughly located between the Sahara and the coastal areas of West Africa.
Contents
[hide]
1 Geography
2 Flora and fauna
3 Climate
4 Culture
5 History
5.1 Early agriculture
5.2 Sahelian kingdoms
5.3 Colonial period
6 Recent droughts
6.1 2010 drought
7 Desertification and soil loss
8 Instability & Violence
9 See also
10 References
11 Sources
12 Further reading
13 External links
Geography[edit]
Camels trample the soil in the semiarid Sahel as they move to water holes, such as this one in Chad.
The lush green of the rainy season Sahelian forest, along the Bamako-Kayes Road in Mali. The trees in the foreground are acacia. Note the large baobab tree.
Sahel people with livestock and azawakh dogs
The Sahel spans 5,400 km (3,360 mi) from the Atlantic Ocean in the west to the Red Sea in the east, in a belt that varies from several hundred to a thousand kilometers (c. 600 miles) in width, covering an area of 3,053,200 square kilometers (1,178,850 sq mi). It is a transitional ecoregion of semi-arid grasslands, savannas, steppes, and thorn shrublands lying between the wooded Sudanian Savanna to the south and the Sahara to the north.[6]
The topography of the Sahel is mainly flat; most of the region lies between 200 and 400 meters (660 and 1,310 ft) in elevation. Several isolated plateaus and mountain ranges rise from the Sahel, but are designated as separate ecoregions because their flora and fauna are distinct from the surrounding lowlands. Annual rainfall varies from around 100–200 mm (4–8 in) in the north of the Sahel to around 600 mm (24 in) in the south.[6]
Flora and fauna[edit]
The Sahel is mostly covered in grassland and savanna, with areas of woodland and shrubland. Grass cover is fairly continuous across the region, dominated by annual grass species such as Cenchrus biflorus, Schoenefeldia gracilis and Aristida stipoides. Species of acacia are the dominant trees, with Acacia tortilis the most common, along with Acacia senegal and Acacia laeta. Other tree species include Commiphora africana, Balanites aegyptiaca, Faidherbia albida, and Boscia senegalensis. In the northern part of the Sahel, areas of desert shrub, including Panicum turgidum and Aristida sieberana, alternate with areas of grassland and savanna. During the long dry season, many trees lose their leaves and the predominantly annual grasses die.
The Sahel was formerly home to large populations of grazing mammals, including the scimitar-horned oryx (Oryx dammah), dama gazelle (Gazella dama), Dorcas gazelle (Gazella dorcas), red-fronted gazelle (Gazella rufifrons), the giant prehistoric buffalo (Pelorovis) and Bubal hartebeest (Alcelaphus busephalus buselaphus), along with large predators like the African wild dog (Lycaon pictus), the Northwest African cheetah (Acinonyx jubatus hecki), the Northeast African cheetah (Acinonyx jubatus soemmeringii), the West African lion (Panthera leo senegalensis) and the East African lion (Panthera leo melanochaita). The larger species have been greatly reduced in number by over-hunting and competition with livestock, and several species are vulnerable (Dorcas gazelle, cheetah, lion and red-fronted gazelle), endangered (Dama gazelle and African wild dog), or extinct (the Scimitar-horned oryx is probably extinct in the wild, and both Pelorovis and the Bubal hartebeest are now extinct).
The seasonal wetlands of the Sahel are important for migratory birds moving within Africa and on the African-Eurasian flyways.[6]
Climate[edit]
Ennedi Plateau is located at the border of the Sahara and the Sahel
The Sahel has a tropical, hot steppe climate (Köppen climate classification BSh). The climate is typically hot, sunny, dry and somewhat windy all year long. The Sahel's climate is similar to, but less extreme than, the climate of the Sahara desert located just to the north.
The Sahel mainly receives a low to a very low amount of precipitation annually. The steppe has a very long, prevailing dry season and a short rainy season. The precipitation is also extremely irregular, and varies considerably from season to season. Most of the rain usually falls during only one or two months, while the other months may remain absolutely dry. The entire Sahel region generally receives between 100 mm and 600 mm of rain yearly. A system of subdivisions often adopted for the Sahelian climate based on annual rainfall is as follows: the Saharan-Sahelian climate, with mean annual precipitation between around 100 and 200 mm (such as Khartoum, Sudan), the strict Sahelian climate, with mean annual precipitation between around 200 and 600 mm (such as Kiffa, Mauritania) and the Sahelian-Sudanese climate, with mean annual precipitation between around 200 and 400 mm (such as Niamey, Niger). The relative humidity in the steppe is low to very low, often between 10% and 25% during the dry season and between 25% and 75% during the rainy season. The least humid places have a relative humidity under 35%.
The Sahel is characterized by constant, intense heat, with an unvarying temperature. The Sahel rarely experiences cold temperatures. During the hottest period, the average high temperatures are generally between 36 and 42 °C (97 and 108 °F) (and even more in the hottest regions), often for more than three months, while the average low temperatures are around 25 to 31 °C (77 to 88 °F). During the "coldest period", the average high temperatures are between 27 and 33 °C (81 and 91 °F) and the average low temperature are between 15 and 21 °C (59 and 70 °F). Everywhere in the Sahel, the average mean temperature is over 18 °C (64 °F) due to the tropical climate.
The Sahel has a high to very high sunshine duration year-round, between 2,700 hours (about 61% of the daylight hours) and 3,500 hours (more than 79% of the daylight hours). The sunshine duration in the Sahel approaches desert levels, and is comparable to that in the Arabian Desert, for example, even though the Sahel is only a steppe and not a desert. The cloud cover is low to very low. For example, Niamey, Niger has 3,082 hours of bright sunshine; Gao, Mali has near 3,385 hours of sunshine; Timbuktu, Mali has 3,409 sunny hours, and N'Djamena, Chad has 3,205 hours of sunlight.[7][8][9][10]
Culture[edit]
Fulani herders in Mali
Traditionally, most of the people in the Sahel have been semi-nomads, farming and raising livestock in a system of transhumance, which is probably the most sustainable way of utilizing the Sahel. The difference between the dry North with higher levels of soil nutrients and the wetter South with more vegetation, is utilized by having the herds graze on high quality feed in the North during the wet season, and trek several hundred kilometers to the South to graze on more abundant, but less nutritious feed during the dry period.[citation needed]
In Western Sahel, polygamy and child marriage are common.[11] Female genital mutilation is also practiced across the Sahel.[11][12]
History[edit]
Early agriculture[edit]
Around 4000 BC, the climate of the Sahara and the Sahel started to become drier at an exceedingly fast pace. This climate change caused lakes and rivers to shrink rather significantly and caused increasing desertification. This, in turn, decreased the amount of land conducive to settlements and caused migrations of farming communities to the more humid climate of West Africa.[13]
Sahelian kingdoms[edit]
Main article: Sahelian kingdoms
Further information: Trans-Saharan trade and Islamization of the Sudan region
Ethnic groups in the Sahel
The Sahelian kingdoms were a series of monarchies centered in the Sahel between the 9th and 18th centuries. The wealth of the states came from controlling the trans-Saharan trade routes across the desert, especially the slave trade with the Islamic world. Their power came from having large pack animals like camels and horses that were fast enough to keep a large empire under central control and were also useful in battle. All of these empires were quite decentralized with member cities having a great deal of autonomy. The first large Sahelian kingdoms emerged after AD 750 and supported several large trading cities in the Niger Bend region, including Timbuktu, Gao, and Djenné.
The Sahel states were hindered from expanding south into the forest zone of the Ashanti and Yoruba peoples as mounted warriors were all but useless in the forests and the horses and camels could not survive the heat and diseases of the region.
Colonial period[edit]
The Western Sahel fell to France in the late 19th century as part of French West Africa. Chad was added in 1900 as part of French Equatorial Africa. The French territories were decolonized in 1960.
The Eastern Sahel (the part in what is now Sudan) did not fall to the European powers but was annexed by Muhammad Ali of Egypt in 1820. It came under British administration as part of the Sultanate of Egypt in 1914. The Sudanese Sahel became part of independent Sudan in 1956, and South Sudan in turn achieved its independence from Sudan proper in 2011.
Recent droughts[edit]
Further information: Sahel drought
For hundreds of years, the Sahel region has experienced regular droughts and megadroughts. One megadrought, from 1450 to 1700, lasted 250 years.[14] There was a major drought in the Sahel in 1914 caused by annual rains far below average, leading to large-scale famine. From 1951 to 2004, the Sahel experienced some of the most consistent and severe droughts in Africa.[15] The 1960s saw a large increase in rainfall in the region, making the northern drier region more accessible. There was a push, supported by governments, for people to move northwards. When the long drought period from 1968 through 1974 began, grazing quickly became unsustainable and large-scale denuding of the terrain followed. Like the drought in 1914, this led to a large-scale famine, but this time somewhat tempered by international visibility and an outpouring of aid. This catastrophe led to the founding of the International Fund for Agricultural Development.
2010 drought[edit]
Main article: 2010 Sahel drought
In June to August 2010 famine struck the Sahel.[16] Niger's crops failed to mature in the heat, 350,000 faced starvation, and 1,200,000 were at risk of famine.[17] In Chad the temperature reached 47.6 °C (117.7 °F) on 22 June in Faya-Largeau, breaking a record set in 1961 at the same location. Niger tied its highest temperature record set in 1998, also on 22 June, at 47.1 °C in Bilma. That record was broken the next day, when Bilma hit 48.2 °C (118.8 °F). The hottest temperature recorded in Sudan was reached on 25 June, at 49.6 °C (121.3 °F) in Dongola, breaking a record set in 1987.[18] Niger reported on 14 July that diarrhea, starvation, gastroenteritis, malnutrition, and respiratory diseases had sickened or killed many children. The new military junta appealed for international food aid and took serious steps to call on overseas help.[19] On 26 July, the heat reached near-record levels over Chad and Niger,[20] and in northern Niger about 20 people reportedly died of dehydration by 27 July.
Desertification and soil loss[edit]
Dust storm in Niamey, Niger
Over-farming, over-grazing, over-population of marginal lands, and natural soil erosion, have caused serious desertification of the region.[21][22] This has had an impact on shelter construction, making it necessary to change the used materials. The Woodless Construction project was introduced in Sahel in 1980 by the Development Workshop, achieving since then a high social impact in the region.[23]
Major dust storms are a frequent occurrence as well. During November 2004, a number of major dust storms hit Chad, originating in the Bodélé Depression.[24] This is a common area for dust storms, occurring on average on 100 days every year.
On 23 March 2010, a major sandstorm hit Mauritania, Senegal, Gambia, Guinea-Bissau, Guinea, and inland Sierra Leone. Another struck in southern Algeria, inland Mauritania, Mali, and northern Ivory Coast[25] at the same time.
Instability & Violence[edit]
Terrorist organizations including Boko Haram, al Qaeda in the Islamic Maghreb (AQIM) operating in the Sahel have contributed to the violence, extremism and instability of the region.[26]
See also[edit]
Africa portal
Community of Sahel-Saharan States
Epidemiology of Meningitis
Green Sahara
2010 Sahel famine
2012 Sahel drought
Sahel drought
Sudan (region)
Sudanian Savanna
Pan Sahel Initiative
Sahara Conservation Fund
Semi-arid climate
Trans-Sahelian Highway
References[edit]
Jump up ^ "Definition grid different of Sahel (British and World English)". Oxford Dictionaries. Retrieved 2015-10-10.
Jump up ^ A System of Modern Geography. E. Huntington & Co. 1834. p. 287.
Jump up ^ http://www.yourdictionary.com/sahel
Jump up ^ "Sahel: $1.6 billion appeal to address widespread humanitarian crisis". United Nations Office for the Coordination of Humanitarian Affairs. Retrieved 24 June 2013.
Jump up ^ The "Sudan region" encompasses not just the history of the Republic of Sudan (whose borders are those of Anglo-Egyptian Sudan, drawn in 1899) but assf the wider Sahel, in Arabic known as bilad as-sudan, "the land of the blacks".
^ Jump up to: a b c "Sahelian Acacia savanna". Terrestrial Ecoregions. World Wildlife Fund. Retrieved 2009-12-07.
Jump up ^ "Niamey Climate Niamey Temperature - Niamey.Climatemps.com".
Jump up ^ "Timbuktu Climate Timbuktu Temperature - Timbuktu.Climatemps.com".
Jump up ^ "Gao Climate Gao Temperature - Gao.Climatemps.com".
Jump up ^ "N'Djamena Climate N'Djamena Temperature - N-Djamena.Climatemps.com".
^ Jump up to: a b "Archived copy" (PDF). Retrieved 5 June 2017.
Jump up ^ "UNICEF WCARO - Overview - Violence against children".
Jump up ^ O'Brien, Patrick K., ed. (2005). Oxford Atlas of World History. New York: Oxford University Press. pp. 22–23.
Jump up ^ Brahic, Catherine. "Africa trapped in mega-drought cycle". New Scientist. Retrieved 17 December 2012.
Jump up ^ Scholl, Adam. "Map Room: Hidden Waters". World Policy Journal. Retrieved 17 December 2012.
Jump up ^ "Drought threatens African humanitarian crisis - Channel 4 News". Channel4.com. 2010-07-01. Retrieved 2010-07-28.
Jump up ^ Foy, Henry (2010-06-21). "Millions face starvation in west Africa, warn aid agencies". The Guardian. London.
Jump up ^ Masters, Jeff. "NOAA: June 2010 the globe's 4th consecutive warmest month on record". Weather Underground. Jeff Masters' WonderBlog. Archived from the original on 19 July 2010. Retrieved 21 July 2010.
Jump up ^ "Niger: famine on the horizon?". France 24. 2010-07-14. Retrieved 2012-10-25.
Jump up ^ "wonder Blog: Weather Underground". Wonder-ground.com. Archived from the original on 2010-06-27. Retrieved 2010-07-28.
Jump up ^ "Causes and Effects of Desertification".
Jump up ^ Schmidt, Laurie J. (18 May 2001). "From the Dust Bowl to the Sahel". NASA.
Jump up ^ "Training and employment of locals. [Social Impact]. WConstruction. The promotion of Woodless Construction in West Africa (1980-2017)". SIOR, Social Impact Open Repository.
Jump up ^ "Dust Storm in the Bodele Depression". NASA. Retrieved 19 June 2010.
Jump up ^ "Earth Snapshot • Sand Storm".
Jump up ^ "Violent Extremism in the Sahel". CSIS.
Sources[edit]
Azam (ed.), Conflict and Growth in Africa: The Sahel, Organisation for Economic Co-operation and Development (1999), ISBN 92-64-17101-0.
(in French) Lagha CHEGROUCHE, "L'arc géopolitique de l'énergie : le croissant énergétique, in Le Soir d'Algérie, 19/12/2010 hi
Further reading[edit]
Dai, A.; Lamb, P.J.; Trenberth, K.E.; Hulme, M.; Jones, P.D.; Xie, P. (2004). "The recent Sahel drought is real" (PDF). International Journal of Climatology. 24 (11): 1323–1331. doi:10.1002/joc.1083 .
Ellis, William S. (August 1987). "The Stricken Land". National Geographic. Vol. 172 no. 2. pp. 140–179. ISSN 0027-9358. OCLC 643483454.
The Growing Crisis in Africa’s Sahel Region: Joint Hearing before the Subcommittee on Africa, Global Health, Global Human Rights, and International Organizations and the Subcommittee on the Middle East and North Africa and the Subcommittee on Terrorism, Nonproliferation and Trade of the Committee in Foreign Affairs, House of Representatives, One Hundred Thirteenth Congress, First Session, May 21, 2013
Moseley, W.G. 2008. “Strengthening Livelihoods in Sahelian West Africa: The Geography of Development and Underdevelopment in a Peripheral Region.” Geographische Rundschau International Edition, 4(4): 44-50. http://works.bepress.com/cgi/viewcontent.cgi?article=1069&context=william_moseley
Simon, L., A. Mattelaer and A. Hadfield (2012) "A Coherent EU Strategy for the Sahel". Brussels: European Parliament (DG for External Policies).
External links[edit]
Wikimedia Commons has media related to Sahel.
"Sahelian Acacia savanna". Terrestrial Ecoregions. World Wildlife Fund.
World Wildlife Fund (2001). "Sahelian Acacia savanna". WildWorld Ecoregion Profile. National Geographic Society. Archived from the original on 2010-03-08.
rain4sahara.org: Rain for the Sahel and Sahara
Authority control
WorldCat Identities
VIAF: 234147245
GND: 4076953-7
BNE: XX451354
Retrieved from "https://en.wikipedia.org/w/index.php?title=Sahel&oldid=837056622"
Categories:
Sahel
Regions of Africa
Afrotropic ecozone
Ecoregions of Africa
Tropical and subtropical grasslands, savannas, and shrublands
Ecoregions of the Central African Republic
Ecoregions of Chad
Ecoregions of Mali
Ecoregions of Mauritania
Ecoregions of Niger
Ecoregions of Senegal
Ecoregions of Sudan
Flora of North Africa
Afrotropic ecoregions
Grasslands of Africa
Hidden categories:
Articles containing Arabic-language text
All articles with unsourced statements
Articles with unsourced statements from July 2013
Pages using div col without cols and colwidth parameters
Articles with French-language external links
Articles with inconsistent citation formats
Wikipedia articles with VIAF identifiers
Wikipedia articles with GND identifiers
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
Edit
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
In other projects
Wikimedia Commons
Wikivoyage
Languages
Afrikaans
العربية
Arpetan
Asturianu
Azərbaycanca
বাংলা
Беларуская
Български
Bosanski
Brezhoneg
Català
Čeština
Cymraeg
Dansk
Deutsch
Eesti
Ελληνικά
Español
Esperanto
Euskara
فارسی
Føroyskt
Français
Frysk
Gaeilge
Galego
한국어
Հայերեն
हिन्दी
Hrvatski
Bahasa Indonesia
Íslenska
Italiano
עברית
ქართული
Қазақша
Kiswahili
Latviešu
Lietuvių
Magyar
Македонски
മലയാളം
मराठी
Bahasa Melayu
Nederlands
日本語
Nordfriisk
Norsk
Norsk nynorsk
Occitan
پنجابی
Polski
Português
Română
Русиньскый
Русский
Scots
Simple English
Slovenčina
Slovenščina
Soomaaliga
Српски / srpski
Srpskohrvatski / српскохрватски
Suomi
Svenska
Татарча/tatarça
ไทย
Türkçe
Українська
اردو
Vèneto
Tiếng Việt
Winaray
Wolof
粵語
Zazaki
中文
68 more
Edit links
This page was last edited on 18 April 2018, at 13:19.
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

key: html

type: local

value: div

attrs: id class

values: mw-page-base noprint

values: mw-head-base noprint

value: a

attrs: id class lang

values: firstHeading firstHeading en

values: siteSub noprint

values: jump-to-nav mw-jump

values:
/wiki/Sahel_(disambiguation)
mw-disambig
Sahel (disambiguation)

values:
note
hatnote navigation-not-searchable

value: img

attrs: alt src width height class srcset data-file-width data-file-height

attrs: href class

attrs: href title

attrs: class style

values:
/wiki/Terrestrial_ecozone
mw-redirect
Terrestrial ecozone

values:
/wiki/Northern_Africa
mw-redirect
Northern Africa

values:
/wiki/Placename_etymology
mw-redirect
Placename etymology

values: Representation in the International Phonetic Alphabet (IPA)

values:
/wiki/Acacia_tortilis
mw-redirect
Acacia tortilis

values:
/wiki/Acacia_senegal
mw-redirect
Acacia senegal

values:
/wiki/Acacia_laeta
mw-redirect
Acacia laeta

values:
/wiki/Faidherbia_albida
mw-redirect
Faidherbia albida

values: Aristida sieberana (page does not exist)

values:
/wiki/Migratory_bird
mw-redirect
Migratory bird

values:
/wiki/African-Eurasian_flyways
mw-redirect
African-Eurasian flyways

values:
/wiki/Hot_semi-arid_climate
mw-redirect
Hot semi-arid climate

values:
/wiki/Sahara_desert
mw-redirect
Sahara desert

values:
/wiki/Fulani_people
mw-redirect
Fulani people

values: This claim needs references to reliable sources. (July 2013)

values:
noprint Inline-Template Template-Fact
white-space:nowrap;

values:
/wiki/Decolonization_of_Africa
mw-redirect
Decolonization of Africa

values: International Fund for Agricultural Development

values:
/wiki/2010_Sahel_drought
mw-redirect
2010 Sahel drought

values:
/wiki/Respiratory_diseases
mw-redirect
Respiratory diseases

values:
/wiki/Military_junta
mw-redirect
Military junta

values: Edit section: Desertification and soil loss

values: display:table-cell;padding:0.2em 0.2em 0.2em 0.3em;vertical-align:middle

values: margin:0.5em 0 0.5em 1em;border:solid #aaa 1px

values:
/wiki/Green_Sahara
mw-redirect
Green Sahara

values: div-col columns column-count column-count-2

values: -moz-column-count: 2; -webkit-column-count: 2; column-count: 2;

values:
nofollow
external free
http://www.yourdictionary.com/sahel

values:
/wiki/Republic_of_Sudan
mw-redirect
Republic of Sudan

values:
nofollow
http://www.niamey.climatemps.com/
external text

values:
nofollow
http://www.timbuktu.climatemps.com/
external text

values:
nofollow
http://www.gao.climatemps.com/
external text

values:
nofollow
http://www.n-djamena.climatemps.com/
external text

values:
nofollow
external text
http://www.eosnap.com/?tag=sand-storm

values: -moz-column-width: 30em; -webkit-column-width: 30em; column-width: 30em; list-style-type: decimal;

values: Organisation for Economic Co-operation and Development

values:
nofollow
external text
//doi.org/10.1002%2Fjoc.1083

values:
/wiki/National_Geographic_(magazine)
mw-redirect
National Geographic (magazine)

values:
nofollow
external text
//www.worldcat.org/issn/0027-9358

values:
nofollow
external text
//www.worldcat.org/oclc/643483454

values:
nofollow
external text
https://purl.fdlp.gov/GPO/gpo42121

values:
nofollow
external text
http://www.rain4sahara.org

values:
nofollow
external text
https://viaf.org/viaf/234147245

values:
nofollow
external text
https://d-nb.info/gnd/4076953-7

values: Category:Tropical and subtropical grasslands, savannas, and shrublands

values: Category:Ecoregions of the Central African Republic

values: Category:Articles containing Arabic-language text

values: Category:All articles with unsourced statements

values: Category:Articles with unsourced statements from July 2013

values: Category:Pages using div col without cols and colwidth parameters

values: Category:Articles with French-language external links

values: Category:Articles with inconsistent citation formats

values: Category:Wikipedia articles with VIAF identifiers

values: Category:Wikipedia articles with GND identifiers

values: Discussion about edits from this IP address [ctrl-alt-n]

values: A list of edits made from this IP address [ctrl-alt-y]

values: You are encouraged to create an account and log in; however, it is not mandatory

values: You're encouraged to log in; however, it's not mandatory. [ctrl-alt-o]

values:
/wiki/Sahel
View the content page [ctrl-alt-c]
c

values: Discussion about the content page [ctrl-alt-t]

values: p-namespaces navigation vectorTabs p-namespaces-label

values:
p-variants
navigation
vectorMenu emptyPortlet
p-variants-label

values:
/w/index.php?title=Sahel&action=edit
Edit this page [ctrl-alt-e]
e

values: Past revisions of this page [ctrl-alt-h]

values: p-views navigation vectorTabs p-views-label

values:
p-cactions
navigation
vectorMenu emptyPortlet
p-cactions-label

values:
mw-wiki-logo
/wiki/Main_Page
Visit the main page

values:
/wiki/Main_Page
Visit the main page [ctrl-alt-z]
z

values: Featured content – the best of Wikipedia

values: Find background information on current events

values:
/wiki/Special:Random
Load a random article [ctrl-alt-x]
x

values: portal navigation p-navigation p-navigation-label

values: Guidance on how to use and edit Wikipedia

values: About the project, what you can do, where to find things

values: A list of recent changes in the wiki [ctrl-alt-r]

values: portal navigation p-interaction p-interaction-label

values: List of all English Wikipedia pages containing links to this page [ctrl-alt-j]

values: Recent changes in pages linked from this page [ctrl-alt-k]

values:
/wiki/Wikipedia:File_Upload_Wizard
Upload files [ctrl-alt-u]
u

values: A list of all special pages [ctrl-alt-q]

values: Permanent link to this revision of the page

values: Link to connected data repository item [ctrl-alt-g]

values: Printable version of this page [ctrl-alt-p]

values: portal navigation p-wikibase-otherprojects p-wikibase-otherprojects-label

values:
https://af.wikipedia.org/wiki/Sahel
Sahel – Afrikaans
af
af
interlanguage-link-target

values:
interlanguage-link interwiki-af
display: none;

values: الساحل (أفريقيا) – Arabic

values:
interlanguage-link interwiki-frp
display: none;

values:
https://ast.wikipedia.org/wiki/Sahel
Sahel – Asturian
ast
ast
interlanguage-link-target

values:
interlanguage-link interwiki-ast
display: none;

values:
https://az.wikipedia.org/wiki/Sahel
Sahel – Azerbaijani
az
az
interlanguage-link-target

values:
interlanguage-link interwiki-az
display: none;

values:
interlanguage-link interwiki-bn
display: none;

values:
interlanguage-link interwiki-be
display: none;

values:
interlanguage-link interwiki-bg
display: none;

values:
https://bs.wikipedia.org/wiki/Sahel
Sahel – Bosnian
bs
bs
interlanguage-link-target

values:
interlanguage-link interwiki-bs
display: none;

values:
https://br.wikipedia.org/wiki/Sahel
Sahel – Breton
br
br
interlanguage-link-target

values:
interlanguage-link interwiki-br
display: none;

values:
https://ca.wikipedia.org/wiki/Sahel
Sahel – Catalan
ca
ca
interlanguage-link-target

values:
interlanguage-link interwiki-ca
display: none;

values:
https://cs.wikipedia.org/wiki/Sahel
Sahel – Czech
cs
cs
interlanguage-link-target

values:
interlanguage-link interwiki-cs
display: none;

values:
https://cy.wikipedia.org/wiki/Sahel
Sahel – Welsh
cy
cy
interlanguage-link-target

values:
interlanguage-link interwiki-cy
display: none;

values:
https://da.wikipedia.org/wiki/Sahel
Sahel – Danish
da
da
interlanguage-link-target

values:
interlanguage-link interwiki-da
display: none;

values:
https://de.wikipedia.org/wiki/Sahelzone
Sahelzone – German
de
de
interlanguage-link-target

values:
interlanguage-link interwiki-de
display: none;

values:
https://et.wikipedia.org/wiki/Sahel
Sahel – Estonian
et
et
interlanguage-link-target

values:
interlanguage-link interwiki-et
display: none;

values: Σαχέλ – Greek

values:
interlanguage-link interwiki-el
display: none;

values:
https://es.wikipedia.org/wiki/Sahel
Sahel – Spanish
es
es
interlanguage-link-target

values:
https://eo.wikipedia.org/wiki/Sahelo
Sahelo – Esperanto
eo
eo
interlanguage-link-target

values:
interlanguage-link interwiki-eo
display: none;

values:
https://eu.wikipedia.org/wiki/Sahel
Sahel – Basque
eu
eu
interlanguage-link-target

values:
interlanguage-link interwiki-eu
display: none;

values: ساحل (منطقه) – Persian

values:
interlanguage-link interwiki-fa
display: none;

values:
https://fo.wikipedia.org/wiki/Sahel
Sahel – Faroese
fo
fo
interlanguage-link-target

values:
interlanguage-link interwiki-fo
display: none;

values:
https://fr.wikipedia.org/wiki/Sahel
Sahel – French
fr
fr
interlanguage-link-target

values:
interlanguage-link interwiki-fr
display: none;

values:
https://fy.wikipedia.org/wiki/Sahel
Sahel – Western Frisian
fy
fy
interlanguage-link-target

values:
interlanguage-link interwiki-fy
display: none;

values:
https://ga.wikipedia.org/wiki/Saiheil
Saiheil – Irish
ga
ga
interlanguage-link-target

values:
interlanguage-link interwiki-ga
display: none;

values:
https://gl.wikipedia.org/wiki/Sahel
Sahel – Galician
gl
gl
interlanguage-link-target

values:
interlanguage-link interwiki-gl
display: none;

values:
interlanguage-link interwiki-ko
display: none;

values:
interlanguage-link interwiki-hy
display: none;

values: सहेल – Hindi

values:
https://hr.wikipedia.org/wiki/Sahel
Sahel – Croatian
hr
hr
interlanguage-link-target

values:
interlanguage-link interwiki-hr
display: none;

values:
https://id.wikipedia.org/wiki/Sahel
Sahel – Indonesian
id
id
interlanguage-link-target

values:
https://is.wikipedia.org/wiki/Sahel
Sahel – Icelandic
is
is
interlanguage-link-target

values:
interlanguage-link interwiki-is
display: none;

values:
https://it.wikipedia.org/wiki/Sahel
Sahel – Italian
it
it
interlanguage-link-target

values:
interlanguage-link interwiki-it
display: none;

values:
interlanguage-link interwiki-he
display: none;

values:
interlanguage-link interwiki-ka
display: none;

values: Сахель – Kazakh

values:
interlanguage-link interwiki-kk
display: none;

values:
https://sw.wikipedia.org/wiki/Sahel
Sahel – Swahili
sw
sw
interlanguage-link-target

values:
interlanguage-link interwiki-sw
display: none;

values:
interlanguage-link interwiki-lv
display: none;

values:
https://lt.wikipedia.org/wiki/Sahelis
Sahelis – Lithuanian
lt
lt
interlanguage-link-target

values:
interlanguage-link interwiki-lt
display: none;

values:
interlanguage-link interwiki-hu
display: none;

values:
interlanguage-link interwiki-ml
display: none;

values:
interlanguage-link interwiki-mr
display: none;

values:
https://ms.wikipedia.org/wiki/Sahel
Sahel – Malay
ms
ms
interlanguage-link-target

values:
interlanguage-link interwiki-nl
display: none;

values:
interlanguage-link interwiki-ja
display: none;

values:
https://frr.wikipedia.org/wiki/Sahel
Sahel – Northern Frisian
frr
frr
interlanguage-link-target

values:
interlanguage-link interwiki-frr
display: none;

values:
https://no.wikipedia.org/wiki/Sahel
Sahel – Norwegian
no
no
interlanguage-link-target

values:
https://nn.wikipedia.org/wiki/Sahel
Sahel – Norwegian Nynorsk
nn
nn
interlanguage-link-target

values:
interlanguage-link interwiki-oc
display: none;

values:
interlanguage-link interwiki-pnb
display: none;

values:
interlanguage-link interwiki-pl
display: none;

values:
https://pt.wikipedia.org/wiki/Sahel
Sahel – Portuguese
pt
pt
interlanguage-link-target

values:
https://ro.wikipedia.org/wiki/Sahel
Sahel – Romanian
ro
ro
interlanguage-link-target

values: Сахел – Rusyn

values:
interlanguage-link interwiki-rue
display: none;

values: Сахель – Russian

values:
https://sco.wikipedia.org/wiki/Sahel
Sahel – Scots
sco
sco
interlanguage-link-target

values:
interlanguage-link interwiki-sco
display: none;

values:
https://simple.wikipedia.org/wiki/Sahel
Sahel – Simple English
simple
simple
interlanguage-link-target

values:
interlanguage-link interwiki-simple
display: none;

values:
https://sk.wikipedia.org/wiki/Sahel
Sahel – Slovak
sk
sk
interlanguage-link-target

values:
https://sl.wikipedia.org/wiki/Sahel
Sahel – Slovenian
sl
sl
interlanguage-link-target

values:
https://so.wikipedia.org/wiki/Sahel
Sahel – Somali
so
so
interlanguage-link-target

values:
interlanguage-link interwiki-so
display: none;

values:
interlanguage-link interwiki-sr
display: none;

values:
https://sh.wikipedia.org/wiki/Sahel
Sahel – Serbo-Croatian
sh
sh
interlanguage-link-target

values:
interlanguage-link interwiki-sh
display: none;

values:
https://fi.wikipedia.org/wiki/Sahel
Sahel – Finnish
fi
fi
interlanguage-link-target

values:
interlanguage-link interwiki-fi
display: none;

values:
https://sv.wikipedia.org/wiki/Sahel
Sahel – Swedish
sv
sv
interlanguage-link-target

values: Сәхил – Tatar

values:
interlanguage-link interwiki-tt
display: none;

values: ซาเฮล – Thai

values:
interlanguage-link interwiki-th
display: none;

values:
https://tr.wikipedia.org/wiki/Sahel
Sahel – Turkish
tr
tr
interlanguage-link-target

values:
https://vec.wikipedia.org/wiki/Sahel
Sahel – Venetian
vec
vec
interlanguage-link-target

values:
interlanguage-link interwiki-vec
display: none;

values:
https://vi.wikipedia.org/wiki/Sahel
Sahel – Vietnamese
vi
vi
interlanguage-link-target

values:
interlanguage-link interwiki-vi
display: none;

values:
https://war.wikipedia.org/wiki/Sahel
Sahel – Waray
war
war
interlanguage-link-target

values:
interlanguage-link interwiki-war
display: none;

values:
https://wo.wikipedia.org/wiki/Sahel
Sahel – Wolof
wo
wo
interlanguage-link-target

values:
interlanguage-link interwiki-wo
display: none;

values:
https://diq.wikipedia.org/wiki/Sahel
Sahel – Zazaki
diq
diq
interlanguage-link-target

values:
interlanguage-link interwiki-diq
display: none;

values: /static/images/wikimedia-button-1.5x.png 1.5x, /static/images/wikimedia-button-2x.png 2x

values: /static/images/poweredby_mediawiki_132x47.png 1.5x, /static/images/poweredby_mediawiki_176x62.png 2x

values: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Sahel rootpage-Sahel skin-vector action-view


text:
Structural steel
From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (July 2009) (Learn how and when to remove this template message)
Various structural steel shapes
Structural steel is a category of steel used for making construction materials in a variety of shapes. Many structural steel shapes take the form of an elongated beam having a profile of a specific cross section. Structural steel shapes, sizes, chemical composition, mechanical properties such as strengths, storage practices, etc., are regulated by standards in most industrialized countries.
Most structural steel shapes, such as I-beams, have high second moments of area, which means they are very stiff in respect to their cross-sectional area and thus can support a high load without excessive sagging.
Contents
1 Common structural shapes
2 Standards
2.1 Standard structural steels (Europe)
2.2 Standard structural steels (USA)
2.2.1 Carbon steels
2.2.2 High strength low alloy steels
2.2.3 Corrosion resistant high strength low alloy steels
2.2.4 Quenched and tempered alloy steels
2.3 CE marking
3 Steel vs. concrete
3.1 Choosing the ideal structural material
3.2 Reinforced concrete
3.3 Structural steel
3.4 Combining steel and reinforced concrete
4 Thermal properties
5 Fire resistance
6 Manufacturing
7 See also
8 References
9 External links
Common structural shapes[edit]
The shapes available are described in many published standards worldwide, and a number of specialist and proprietary cross sections are also available.
A steel I-beam, in this case used to support timber joists in a house.
I-beam (I-shaped cross-section - in Britain these include Universal Beams (UB) and Universal Columns (UC); in Europe it includes the IPE, HE, HL, HD and other sections; in the US it includes Wide Flange (WF or W-Shape) and H sections)
Z-Shape (half a flange in opposite directions)
HSS-Shape (Hollow structural section also known as SHS (structural hollow section) and including square, rectangular, circular (pipe) and elliptical cross sections)
Angle (L-shaped cross-section)
Structural channel, or C-beam, or C cross-section
Tee (T-shaped cross-section)
Rail profile (asymmetrical I-beam)
Railway rail
Vignoles rail
Flanged T rail
Grooved rail
Bar, a piece of metal, rectangular cross sectioned (flat) and long, but not so wide so as to be called a sheet.
Rod, a round or square and long piece of metal, see also rebar and dowel.
Plate, metal sheets thicker than 6 mm or 1⁄4 in.
Open web steel joist
While many sections are made by hot or cold rolling, others are made by welding together flat or bent plates (for example, the largest circular hollow sections are made from flat plate bent into a circle and seam-welded).[1]
The terms angle iron, channel iron, and sheet iron have been in common use since before wrought iron was replaced by steel for commercial purposes. They have lived on after the era of commercial wrought iron and are still sometimes heard today, informally, in reference to steel angle stock, channel stock, and sheet, despite that they are misnomers (compare "tin foil" still sometimes used informally for aluminum foil). In formal writing for metalworking contexts, accurate terms like angle stock, channel stock, and sheet are used.
Standards[edit]
Standard structural steels (Europe)[edit]
Most steels used throughout Europe are specified to comply with the European standard EN 10025. However, many national standards also remain in force.[citation needed]
Typical grades are described as 'S275J2' or 'S355K2W'. In these examples, 'S' denotes structural rather than engineering steel; 275 or 355 denotes the yield strength in newtons per square millimetre or the equivalent megapascals; J2 or K2 denotes the materials toughness by reference to Charpy impact test values; and the 'W' denotes weathering steel. Further letters can be used to designate fine grain steel ('N' or 'NL'); quenched and tempered steel ('Q' or 'QL'); and thermomechanically rolled steel ('M' or 'ML').

1. S275JOH Specification S275JOH is steel grade in EN 10219 specification, EN 10210 standard. And the most widely used specification is EN10219 standard, which is Cold formed welded structural hollow sections of non-alloy and fine grain steels.
EN10219-1 specifies the technical delivery conditions for cold formed welded structural hollow sections of circular, square or rectangular forms and applies to structural hollow sections formed cold without subsequent heat treatment.
Requirements for S275JOH pipe tolerances, dimensions and sectional s275 pipe properties are contained in EN 10219-2.
2. S275JOH Steel Pipes manufacture Process
The steel manufacturing process shall be at the discretion of the steel producer. S275JOH carbon steel pipes can be made in ERW, SAW or seamless process. All S275JOH steel material and S275JOH pipes should conform to EN10219 standards. [2]

The normal yield strength grades available are 195, 235, 275, 355, 420, and 460, although some grades are more commonly used than others e.g. in the UK, almost all structural steel is grades S275 and S355. Higher grades are available in quenched and tempered material (500, 550, 620, 690, 890 and 960 - although grades above 690 receive little if any use in construction at present).
A set of Euronorms define the shape of a set of standard structural profiles:
European I-beam: IPE - Euronorm 19-57
European I-beam: IPN - DIN 1025-1
European flange beams: HE - Euronorm 53-62
European channels: UPN - DIN 1026-1
European cold formed IS IS 800-1
Standard structural steels (USA)[edit]
Steels used for building construction in the US use standard alloys identified and specified by ASTM International. These steels have an alloy identification beginning with A and then two, three, or four numbers. The four-number AISI steel grades commonly used for mechanical engineering, machines, and vehicles are a completely different specification series.
The standard commonly used structural steels are:[3]
Carbon steels[edit]
A36 - structural shapes and plate.
A53 - structural pipe and tubing.
A500 - structural pipe and tubing.
A501 - structural pipe and tubing.
A529 - structural shapes and plate.
High strength low alloy steels[edit]
A441 - structural shapes and plates.
A572 - structural shapes and plates.
A618 - structural pipe and tubing.
A992 - Possible applications are W or S I-Beams.
A913 - Quenched and Self Tempered (QST) W shapes.
A270 - structural shapes and plates.
A521 - structural plates
Corrosion resistant high strength low alloy steels[edit]
A243 - structural shapes and plates.
A588 - structural shapes and plates.
Quenched and tempered alloy steels[edit]
A514 - structural shapes and plates.
A517 - boilers and pressure vessels.
Eglin steel - Inexpensive aerospace and weaponry items.
Non-preload bolt assembly (EN 15048)
Pre-load bolt assembly (EN 14399)
CE marking[edit]
The concept of CE marking for all construction products and steel products is introduced by the Construction Products Directive (CPD). The CPD is a European Directive that ensures the free movement of all construction products within the European Union.
Because steel components are "safety critical", CE Marking is not allowed unless the Factory Production Control (FPC) system under which they are produced has been assessed by a suitable certification body that has been approved to the European Commission.[4]
In the case of steel products such as sections, bolts and fabricated steelwork the CE Marking demonstrates that the product complies with the relevant harmonized standard.[5]
For steel structures the main harmonized standards are:
Steel sections and plate - EN 10025-1
Hollow sections - EN 10219-1 and EN 10210-1
Pre-loadable bolts - EN 14399-1
Non-preloadable bolts - EN 15048-1
Fabricated steel - EN 1090 -1
The standard that covers CE Marking of structural steelwork is EN 1090-1. The standard has come into force in late 2010. After a transition period of two years, CE Marking will become mandatory in most European Countries sometime early in 2012.[6] The official end date of the transition period is July 1, 2014.
Steel vs. concrete[edit]
Choosing the ideal structural material[edit]
This article reads like a textbook and may require cleanup. Please help to improve this article to make it neutral in tone and meet Wikipedia's quality standards. (June 2018)
Most construction projects require the use of hundreds of different materials. These range from concrete of all different specifications, structural steel of different specifications, clay, mortar, ceramics, wood, etc. In terms of a load bearing structural frame, they will generally consist of structural steel, concrete, masonry, and/or wood, using a suitable combination of each to produce an efficient structure. Most commercial and industrial structures are primarily constructed using either structural steel or reinforced concrete. When designing a structure, an engineer must decide which, if not both, material is most suitable for the design. There are many factors considered when choosing a construction material. Cost is commonly the controlling element; however, other considerations such as weight, strength, constructability, availability, sustainability, and fire resistance will be taken into account before a final decision is made.
Cost - The cost of these construction materials will depend entirely on the geographical location of the project and the availability of the materials. Just as the price of gasoline fluctuates, so do the prices of cement, aggregate, steel, etc. Reinforced concrete derives about half of its construction costs from the required form-work. This refers to the lumber necessary to build the "box" or container in which the concrete is poured and held until it cures. The expense of the forms makes precast concrete a popular option for designers due to the reduced costs and time.[7] Due to the fact that steel is sold by weight it is the responsibility of the structural designer to specify the lightest members possible while still maintaining a safe structural design. An additional method of reducing expenditures in design is to use many of the same size steel members as opposed to many unique members.[8]
Strength/weight ratio - Construction materials are commonly categorized by their strength to weight ratio, or specific strength. This is defined as the strength of a material over its density. This gives an engineer an indication as to how useful the material is in comparison to its weight, with the weight being a direct indication of its cost (typically) and ease of construction. Concrete is typically ten times stronger in compression than in tension, giving it a higher strength to weight ratio in compression, only.[9]
Sustainability - Many construction companies and material vendors are making changes to be a more environmentally friendly company. Sustainability has become an entirely new consideration for materials that are to be placed into the environment for generations of time. A sustainable material will be one that has minimal effect on the environment, both at the time of installation as well as throughout the life cycle of the material. Reinforced concrete and structural steel both have the ability to be a sustainable construction option, if used properly. Over 80% of structural steel members fabricated today come from recycled metals, called A992 steel. This member material is cheaper, as well as having a higher strength to weight ratio, than previously used steel members (A36 grade).[10] Reinforced concrete can also be a very sustainable option. Concrete's material components are naturally occurring materials that are not harmful to the environment. Also, concrete can now be poured to be permeable, allowing the flow of water through a paved surface and therefore reducing the necessary infrastructural construction that causes further potential disturbance to the environment. Concrete can also be crushed and used as aggregate in future concrete applications, meaning it doesn't necessarily have to be used as a land fill.[11]
Fire resistance - One of the most dangerous hazards to a building is a fire hazard. This is especially true in dry, windy climates and for structures constructed using wood. Special considerations must be taken into account with structural steel to ensure it is not under a dangerous fire hazard condition. Reinforced concrete characteristically does not pose a threat in the event of fire and even resists the spreading of fire, as well as temperature changes. This makes concrete an excellent insulation, improving the sustainability of the building it surrounds by reducing the required energy to maintain climate.[9]
Corrosion - When choosing a structural material, it is important to consider the life cycle of the building. Some materials are susceptible to corrosion from their surrounding elements, such as water, heat, humidity, or salt. Special considerations must be taken into account during the installation of a structural material to prevent any potential corrosion hazards. This must also be made clear to the occupants of the building because there may or may not be a necessary maintenance requirement to prevent corrosion. For example, structural steel cannot be exposed to the environment because any moisture, or other contact with water, will cause it to rust. When the steel rusts it compromises the structural integrity of the building and poses a potential danger to the residual or surrounding occupants.[9]
Reinforced concrete[edit]
Characteristics - Generally consisting of portland cement, water, construction aggregate (coarse and fine), and steel reinforcing bars (rebar), concrete is cheaper in comparison to structural steel.
Strength - Concrete is a composite material with relatively high compressive strength properties, but lacking in tensile strength/ductility. This inherently makes concrete a useful material for carrying the weight of a structure. Concrete reinforced with steel rebar give the structure a stronger tensile capacity, as well as an increase in ductility and elasticity.
Constructability - Reinforced concrete must be poured and left to set, or harden. After setting (typically 1–2 days), a concrete must cure, the process in which concrete experiences a chemical reaction between the cementitious particles and the water. The curing process is complete after 28 days; however, construction may continue after 1–2 weeks, depending on the nature of the structure. Concrete can be constructed into nearly any shape and size. Approximately half of the cost of using reinforced concrete in a structural project is attributed to the construction of the form-work. In order to save time, and therefore costs, structural concrete members may be pre-cast. This refers to a reinforced concrete beam, girder, or column being poured off site and left to cure. After the curing process, the concrete member may be delivered to the construction site and installed as soon as it is needed. Since the concrete member was cured off location beforehand, construction may continue immediately after erection.[9]
Fire resistance - Concrete has excellent fire resistance properties, requiring no additional construction costs to adhere to the International Building Code (IBC) fire protection standards. However, concrete buildings will still likely use other materials that are not fire resistant. Therefore, a designer must still take into account the use of the concrete and where it will require fire hazardous materials in order to prevent future complications in the overall design.
Corrosion - Reinforced concrete, when constructed properly, has excellent corrosion resistance properties. Concrete is not only resistant to water, but needs it to cure and develop its strength over time. However, the steel reinforcement in the concrete must not be exposed in order to prevent its corrosion as this could significantly reduce the ultimate strength of the structure. The American Concrete Institute provides the necessary design specifications for an engineer to ensure there is enough concrete covering any steel reinforcement to prevent exposure to water. This cover distance must be specified because concrete will inevitable crack at locations carrying tension, or locations containing reinforcing bars for the purpose of carrying said tension. If the concrete cracks, it provides a path for water to travel directly to the reinforcing bars.[9] Some reinforcing bars are coated in epoxy as a second order measure of preventing corrosion due to water contact. This method induces higher costs on the overall project, however, due to the higher cost of the epoxy coated bars. Also, when using epoxy coated bars, reinforced concrete members must be designed larger, as well as stronger, in order to balance the loss of friction between the reinforcing bars and concrete. This friction is referred to as bond strength, and it is vital to the structural integrity of a concrete member.[7]
Structural steel[edit]
Characteristics - Structural steel differs from concrete in its attributed compressive strength as well as tensile strength.[9]
Strength - Having high strength, stiffness, toughness, and ductile properties, structural steel is one of the most commonly used materials in commercial and industrial building construction.[12]
Constructability - Structural steel can be developed into nearly any shape, which are either bolted or welded together in construction. Structural steel can be erected as soon as the materials are delivered on site, whereas concrete must be cured at least 1–2 weeks after pouring before construction can continue, making steel a schedule-friendly construction material.[9]
Fire resistance - Steel is inherently a noncombustible material. However,when heated to temperatures seen in a fire scenario, the strength and stiffness of the material is significantly reduced. The International Building Code requires steel be enveloped in sufficient fire-resistant materials, increasing overall cost of steel structure buildings.[12]
Corrosion - Steel, when in contact with water, can corrode, creating a potentially dangerous structure. Measures must be taken in structural steel construction to prevent any lifetime corrosion. The steel can be painted, providing water resistance. Also, the fire resistance material used to envelope steel is commonly water resistant.[9]
Mold - Steel provides a less suitable surface environment for mold to grow than wood.[13]
The tallest structures today (commonly called "skyscrapers" or high-rise) are constructed using structural steel due to its constructability, as well as its high strength-to-weight ratio. In comparison, concrete, while being less dense than steel, has a much lower strength-to-weight ratio. This is due to the much larger volume required for a structural concrete member to support the same load; steel, though denser, does not require as much material to carry a load. However, this advantage becomes insignificant for low-rise buildings, or those with several stories or less. Low-rise buildings distribute much smaller loads than high-rise structures, making concrete the economical choice. This is especially true for simple structures, such as parking garages, or any building that is a simple, rectilinear shape.[14]
Structural steel and reinforced concrete are not always chosen solely because they are the most ideal material for the structure. Companies rely on the ability to turn a profit for any construction project, as do the designers. The price of raw materials (steel, cement, coarse aggregate, fine aggregate, lumber for form-work, etc.) is constantly changing. If a structure could be constructed using either material, the cheapest of the two will likely control. Another significant variable is the location of the project. The closest steel fabrication facility may be much further from the construction site than the nearest concrete supplier. The high cost of energy and transportation will control the selection of the material as well. All of these costs will be taken into consideration before the conceptual design of a construction project is begun.[9]
Combining steel and reinforced concrete[edit]
Structures consisting of both materials utilize the benefits of structural steel and reinforced concrete. This is already common practice in reinforced concrete in that the steel reinforcement is used to provide steel's tensile strength capacity to a structural concrete member. A commonly seen example would be parking garages. Some parking garages are constructed using structural steel columns and reinforced concrete slabs. The concrete will be poured for the foundational footings, giving the parking garage a surface to be built on. The steel columns will be connected to the slab by bolting and/or welding them to steel studs extruding from the surface of the poured concrete slab. Pre-cast concrete beams may be delivered on site to be installed for the second floor, after which a concrete slab may be poured for the pavement area. This can be done for multiple stories.[14] A parking garage of this type is just one possible example of many structures that may use both reinforced concrete and structural steel.
A structural engineer understands that there are an infinite number of designs that will produce an efficient, safe, and affordable building. It is the engineer's job to work alongside the owner(s), contractor(s), and all other parties involved to produce an ideal product that suits everyone's needs.[9] When choosing the structural materials for their structure, the engineer has many variables to consider, such as the cost, strength/weight ratio, sustainability of the material, constructability, etc.
Thermal properties[edit]
The properties of steel vary widely, depending on its alloying elements.
The austenizing temperature, the temperature where a steel transforms to an austenite crystal structure, for steel starts at 900 °C (1,650 °F) for pure iron, then, as more carbon is added, the temperature falls to a minimum 724 °C (1,335 °F) for eutectic steel (steel with only .83% by weight of carbon in it). As 2.1% carbon (by mass) is approached, the austenizing temperature climbs back up, to 1,130 °C (2,070 °F). Similarly, the melting point of steel changes based on the alloy.
The lowest temperature at which a plain carbon steel can begin to melt, its solidus, is 1,130 °C (2,070 °F). Steel never turns into a liquid below this temperature. Pure Iron ('Steel' with 0% Carbon) starts to melt at 1,492 °C (2,718 °F), and is completely liquid upon reaching 1,539 °C (2,802 °F). Steel with 2.1% Carbon by weight begins melting at 1,130 °C (2,070 °F), and is completely molten upon reaching 1,315 °C (2,399 °F). 'Steel' with more than 2.1% Carbon is no longer Steel, but is known as Cast iron.[15]
Fire resistance[edit]
Metal deck and open web steel joist receiving spray fireproofing plaster, made of polystyrene-leavened gypsum.
Steel loses strength when heated sufficiently. The critical temperature of a steel member is the temperature at which it cannot safely support its load.[16] Building codes and structural engineering standard practice defines different critical temperatures depending on the structural element type, configuration, orientation, and loading characteristics. The critical temperature is often considered the temperature at which its yield stress has been reduced to 60% of the room temperature yield stress.[17] In order to determine the fire resistance rating of a steel member, accepted calculations practice can be used,[18] or a fire test can be performed, the critical temperature of which is set by the standard accepted to the Authority Having Jurisdiction, such as a building code. In Japan, this is below 400 °C[citation needed]. In China, Europe and North America (e.g., ASTM E-119), this is approximately 1000–1300 °F[19] (530-810 °C). The time it takes for the steel element that is being tested to reach the temperature set by the test standard determines the duration of the fire-resistance rating. Heat transfer to the steel can be slowed by the use of fireproofing materials, thus limiting steel temperature. Common fireproofing methods for structural steel include intumescent, endothermic, and plaster coatings as well as drywall, calcium silicate cladding, and mineral wool insulating blankets.[20]
Concrete building structures often meet code required fire-resistance ratings, as the concrete thickness over the steel rebar provides sufficient fire resistance. However, concrete can be subject to spalling, particularly if it has an elevated moisture content. Although additional fireproofing is not often applied to concrete building structures, it is sometimes used in traffic tunnels and locations where a hydrocarbon fuel fire is more likely, as flammable liquid fires provides more heat to the structural element as compared to a fire involving ordinary combustibles during the same fire period. Structural steel fireproofing materials include intumescent, endothermic and plaster coatings as well as drywall, calcium silicate cladding, and mineral or high temperature insulation wool blankets. Attention is given to connections, as the thermal expansion of structural elements can compromise fire-resistance rated assemblies.
Manufacturing[edit]
Cutting workpieces to length is usually done with a bandsaw.
A beam drill line (drill line) has long been considered an indispensable way to drill holes and mill slots into beams, channels and HSS elements. CNC beam drill lines are typically equipped with feed conveyors and position sensors to move the element into position for drilling, plus probing capability to determine the precise location where the hole or slot is to be cut.
For cutting irregular openings or non-uniform ends on dimensional (non-plate) elements, a cutting torch is typically used. Oxy-fuel torches are the most common technology and range from simple hand-held torches to automated CNC coping machines that move the torch head around the structural element in accordance with cutting instructions programmed into the machine.
Fabricating flat plate is performed on a plate processing center where the plate is laid flat on a stationary 'table' and different cutting heads traverse the plate from a gantry-style arm or "bridge". The cutting heads can include a punch, drill or torch.
See also[edit]
Diamond plate
Dowel
Flame cleaning
Flange
Gusset plate
Light steel structure
Open web steel joist
Railway rail
Structural engineering
Structural shape rolling
References[edit]
Jump up ^ "Steel structure workshop". Retrieved 2 March 2017.
Jump up ^ "EN10219 S275JOH Carbon Steel Pipe". CHINA HYSP PIPE.
Jump up ^ Manual of Steel Construction, 8th Edition, 2nd revised printing, American Institute of Steel Construction, 1987, ch 1 page 1-5
Jump up ^ The website of the British Constructional Steelwork Association Ltd. - SteelConstruction.org:CE-Marking.08/02/2011.
Jump up ^ Guide to the CE Marking of Structural Steelwork, BCSA Publication No. 46/08. p.1.
Jump up ^ Manufacturer Certification in Compliance with EN 1090, 09.08.2011
^ Jump up to: a b Levitt, M. Precast Concrete. ISBN 978-0-85334-994-5.
Jump up ^ Popescu, Calin. Estimating Building Costs.
^ Jump up to: a b c d e f g h i j Handbook of Structural Engineering. CRC Press. 1997. ISBN 978-0-8493-2674-5.
Jump up ^ Zaharia, Raul. Designing Steel Structures for Fire Safety. ISBN 978-0-415-54828-1.
Jump up ^ Russ, Tom. Sustainability and Design Ethics. ISBN 978-1-4398-0854-2.
^ Jump up to: a b Chen, Wai-Fah (2005). Principles of Structural Design. ISBN 978-0-8493-7235-3.
Jump up ^ Armstrong, Robert (7 March 2014). "Properties and Prevention of Household Mold". Absolute Steel. Retrieved 2 November 2014.
^ Jump up to: a b Taranath, Bungale. Reinforced Concrete Design of Tall Buildings. ISBN 978-1-4398-0480-3.
Jump up ^ http://www.msm.cam.ac.uk/phase-trans/images/FeC.gif
Jump up ^ "What Is Structural Steel? - Steel Fabrication Services". Steel Fabrication Services. 2016-04-21. Retrieved 2016-10-26.
Jump up ^ Industrial fire protection engineering, Robert G. Zalosh, copyright 2003 pg.58
Jump up ^ Zalosh, Pg. 70
Jump up ^ Zalosh, Table 3.3
Jump up ^ Best Practice Guidelines for Structural Fire Resistance Design of Concrete and Steel Buildings, NIST Technical Note 1681, L. T. Phan, J. L. Gross, and T. P. McAllister, 2010. (View report)
External links[edit]
Wikiquote has quotations related to: Structural steel
Wikimedia Commons has media related to Structural Steel.
Guide to the CE Marking of Structural Steelwork, BCSA Publication No. 46/08.
Encyclopedia for steel construction information
show
v
t
e
Metalworking
show
v
t
e
Casting
Processes
Centrifugal
Continuous
Die
Evaporative-pattern
Full mold
Lost foam
Investment (Lost wax)
Permanent mold
Plaster mold
Sand
Semi-solid metal
Shaw process
Shell molding
Spin
Components
Chill
Cope and drag
Core
Flask
Molding sand
Pattern
Riser
Sprue
Terminology
Casting defects
Draft
Dross
Ingot
Semi-finished casting products
Slag
show
v
t
e
Forming, fabrication, and finishing
General
Fabrication
Piece work
Sheet metal
Forming processes
Coining
Drawing
Electrohydraulic forming
Electromagnetic forming
Explosive forming
Forging
Hydroforming
Progressive stamping
Punching
Rolling
Sinking
Spinning
Swaging
Tube bending
Joining processes
Brazing
Crimping
Riveting
Soldering
Welding
Finishing processes
Anodizing
Galvanizing
Heat treating
Mass finishing
Patination
Peening
Plating
Polishing
show
v
t
e
Machining and computing
Computer-aided
engineering
2.5D
CAD
CAM
G-code
Numerical control (NC and CNC)
Stewart platform
Drilling and
threading
Die head
Drill
Drill bit
Drill bit shank
Drill bit sizes
Drilling
List of drill and tap sizes
Tap and die
Tap wrench
Threading
Grinding and
lapping
Abrasive
Angle grinder
Bench grinder
Coated abrasives
Cylindrical grinder
Diamond plate
Flick grinder
Grinding
Grinding dresser
Grinding machine
Grinding wheel
Jig grinder
Lapping
Sanding
Sharpening stone
Spark testing
Surface grinder
Tool and cutter grinder
Machining
Boring
Broaching
Electrical discharge machining
Electrochemical machining
Electron beam machining
Endmill
Engraving
Facing
Hobbing
Jig borer
Machine tool
Machining
Metal lathe
Milling cutter
Milling machine
Pantograph
Photochemical machining
Planer
Reamer
Rotary transfer machine
Shaper
Turning
Ultrasonic machining
Machine tooling
Angle plate
Chuck
Collet
Fixture
Indexing head
Jig
Lathe center
Machine taper
Magnetic base
Mandrel
Rotary table
Wiggler
Terminology
Cutting fluid
Machining vibrations
Speeds and feeds
Swarf
Tolerance
Tool and die making
Tramp oil
show
v
t
e
Smithing
Smiths
Blacksmith
Bladesmith
Coppersmith
Goldsmith
Gunsmith
Locksmith
Pewtersmith
Silversmith
Tinsmith
Processes
Forging
Pattern welding
Planishing
Raising
Sinking
Swaging
Tools
Anvil
Forge
Fuller
Hammer
Hardy tools
Pritchel
Steam hammer
Swage block
Trip hammer
show
v
t
e
Tools
Cutting machines
Bandsaw
Cold saw
Laser
Miter saw
Plasma
Water jet cutter
Cutting tools
Broach
Burr
Chisel
Counterbore
Countersink
End mill
File
Hand scraper
Milling cutter
Nibbler
Reamer
Shears
Tipped tool
Tool bit
Forming tools
Brake
Die
English wheel
Hydraulic press
Machine press
Punch press
Screw press
Stamping press
Hand tools
Clamp
Combination square
Drift pin
Hacksaw
Hammer
Hand scraper
Machinist square
Needlegun scaler
Piercing saw
Pliers
Punch
Scriber
Tap and die
Tongs
Vise
Workbench
Wrench
Machine tooling
Angle plate
Chuck
Collet
Fixture
Indexing head
Jig
Lathe center
Machine taper
Magnetic base
Mandrel
Rotary table
Wiggler
Measuring instruments
Bore gauge
Caliper
Center gauge
Dial indicator
Engineer's blue
Engineer's spirit level
Feeler gauge
Gauge
Gauge block
Go/no go gauge
Height gauge
Machinist square
Marking blue
Marking gauge
Marking out
Micrometer
Optical comparator
Radius gauge
Ruler
Sine bar
Straightedge
Surface plate
Tape measure
Thread pitch gauge
Vernier scale
Smithing tools
Anvil
Forge
Fuller
Hardy tools
Pritchel
Steam hammer
Swage block
Trip hammer
show
v
t
e
Welding
Arc welding
Atomic hydrogen (Athydo/AHW)
Electrogas (EGW)
Flash
Flux-cored (FCAW)
Gas metal (Microwire/MIG/GMAW)
Gas tungsten (Heliarc/TIG/GTAW)
Plasma (PAW)
Shielded metal (Stick/MMA/SMAW)
Submerged (SAW)
Other processes
Electric resistance (ERW)
Electron beam (EBW)
Electroslag (ESW)
Exothermic
Forge
Friction
Friction stir (FSW)
Friction stud
Laser beam (LBW)
Laser-hybrid
Magnetic pulse
Oxyacetylene (OAW)
Spot (RSW)
Ultrasonic
Upset
Equipment
Electrode
Filler metal
Helmet
Power supply
Robot
Shielding gas
Related terms
Heat-affected zone
Photokeratitis
Residual stress
Weldability
Casting
Fabrication
Forming
Jewellery
Machining
Metallurgy
Smithing
Tools and terminology
Welding
Authority control
NDL: 00572809
Retrieved from "https://en.wikipedia.org/w/index.php?title=Structural_steel&oldid=847252677"
Categories:
Structural steel
Structural engineering
Steels
Hidden categories:
Articles needing additional references from July 2009
All articles needing additional references
All articles with unsourced statements
Articles with unsourced statements from August 2011
Wikipedia articles needing style editing from June 2018
All articles needing style editing
Articles with unsourced statements from July 2011
Wikipedia articles with NDL identifiers
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
Edit
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
In other projects
Wikimedia Commons
Languages
Български
Català
Deutsch
Español
Euskara
हिन्दी
Hrvatski
Italiano
Қазақша
Latina
日本語
Polski
Português
Русский
Slovenščina
Srpskohrvatski / српскохрватски
Suomi
Svenska
Українська
Tiếng Việt
中文
12 more
Edit links
This page was last edited on 24 June 2018, at 00:03 (UTC).
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

values: mw-page-base noprint

values: mw-head-base noprint

values: firstHeading firstHeading en

values: siteSub noprint

attrs: class href

values: mw-jump-link #mw-head

values: mw-jump-link #p-search

attrs: alt src width height srcset data-file-width data-file-height

value: td

value: b

values: Help:Introduction to referencing with Wiki Markup/1

value: span

value: i

value: small

values: plainlinks metadata ambox ambox-content ambox-Refimprove

values:
/wiki/Construction_material
mw-redirect
Construction material

values: checkbox button toctogglecheckbox toctogglecheckbox display:none

values:
/wiki/Square_(geometry)
mw-redirect
Square (geometry)

values:
/wiki/Pipe_(material)
mw-redirect
Pipe (material)

values:
/wiki/Rail_tracks#Rail
mw-redirect
Rail tracks

values:
/wiki/Vignoles_rail
mw-redirect
Vignoles rail

values:
/wiki/Flanged_T_rail
mw-redirect
Flanged T rail

values:
/wiki/Hot_rolling
mw-redirect
Hot rolling

values:
/wiki/Cold_rolling
mw-redirect
Cold rolling

values: Edit section: Standard structural steels (Europe)

values: This claim needs references to reliable sources. (August 2011)

values:
noprint Inline-Template Template-Fact
white-space:nowrap;

values:
/wiki/Yield_strength
mw-redirect
Yield strength

values: Edit section: Standard structural steels (USA)

values:
/wiki/AISI_steel_grades
mw-redirect
AISI steel grades

values: Edit section: High strength low alloy steels

values: Edit section: Corrosion resistant high strength low alloy steels

values: Edit section: Quenched and tempered alloy steels

values:
/wiki/EU_Directive
mw-redirect
EU Directive

values:
/wiki/Factory_Production_Control
mw-redirect
Factory Production Control

values: Edit section: Choosing the ideal structural material

values:
plainlinks metadata ambox ambox-style
presentation

values: Edit section: Combining steel and reinforced concrete

values:
/wiki/Yield_stress
mw-redirect
Yield stress

values: This claim needs references to reliable sources. (July 2011)

values:
/wiki/Fireproofing_materials
mw-redirect
Fireproofing materials

values:
/wiki/Light_steel_structure
mw-redirect
Light steel structure

values: -moz-column-width: 30em; -webkit-column-width: 30em; column-width: 30em;

values:
nofollow
http://www.xgz1996.com/
external text

values:
nofollow
external text
https://dx.doi.org/10.6028/NIST.TN.1681

values:
nofollow
external text
http://www.steelconstruction.info

values: Template talk:Metalworking navbox/cast (page does not exist)

values: nowraplinks collapsible collapsed navbox-subgroup mw-collapsible mw-collapsed mw-made-collapsible

values: Template talk:Metalworking navbox/form (page does not exist)

values: Template talk:Metalworking navbox/mach (page does not exist)

values:
/wiki/Milling_machine
mw-redirect
Milling machine

values: Template talk:Metalworking navbox/smith (page does not exist)

values: Template talk:Metalworking navbox/tool (page does not exist)

values: Indicator (distance amplifying instrument)

values: Template talk:Metalworking navbox/weld (page does not exist)

values:
/wiki/Electron_beam_welding
mw-redirect
Electron beam welding

values: nowraplinks hlist collapsible autocollapse navbox-inner mw-collapsible mw-made-collapsible mw-collapsed

values: navigation navbox Metalworking padding:3px

attrs: alt src width height style srcset data-file-width data-file-height

values: Category:Articles needing additional references from July 2009

values: Category:All articles needing additional references

values: Category:All articles with unsourced statements

values: Category:Articles with unsourced statements from August 2011

values: Category:Wikipedia articles needing style editing from June 2018

values: Category:All articles needing style editing

values: Category:Articles with unsourced statements from July 2011

values: Category:Wikipedia articles with NDL identifiers

values: Discussion about edits from this IP address [ctrl-alt-n]

values: A list of edits made from this IP address [ctrl-alt-y]

values: You are encouraged to create an account and log in; however, it is not mandatory

values: You're encouraged to log in; however, it's not mandatory. [ctrl-alt-o]

values:
/wiki/Structural_steel
View the content page [ctrl-alt-c]
c

values: Discussion about the content page [ctrl-alt-t]

values: p-namespaces navigation vectorTabs p-namespaces-label

values:
p-variants
navigation
vectorMenu emptyPortlet
p-variants-label

values: Past revisions of this page [ctrl-alt-h]

values: p-views navigation vectorTabs p-views-label

values:
p-cactions
navigation
vectorMenu emptyPortlet
p-cactions-label

values:
mw-wiki-logo
/wiki/Main_Page
Visit the main page

values:
/wiki/Main_Page
Visit the main page [ctrl-alt-z]
z

values: Featured content – the best of Wikipedia

values: Find background information on current events

values:
/wiki/Special:Random
Load a random article [ctrl-alt-x]
x

values: portal navigation p-navigation p-navigation-label

values: Guidance on how to use and edit Wikipedia

values: About the project, what you can do, where to find things

values: A list of recent changes in the wiki [ctrl-alt-r]

values: portal navigation p-interaction p-interaction-label

values: List of all English Wikipedia pages containing links to this page [ctrl-alt-j]

values: Recent changes in pages linked from this page [ctrl-alt-k]

values:
/wiki/Wikipedia:File_Upload_Wizard
Upload files [ctrl-alt-u]
u

values: A list of all special pages [ctrl-alt-q]

values: Permanent link to this revision of the page

values: Link to connected data repository item [ctrl-alt-g]

values: Printable version of this page [ctrl-alt-p]

values: portal navigation p-wikibase-otherprojects p-wikibase-otherprojects-label

values: Конструкционни стомани – Bulgarian

values:
interlanguage-link interwiki-bg
display: none;

values:
interlanguage-link interwiki-ca
display: none;

values:
https://de.wikipedia.org/wiki/Baustahl
Baustahl – German
de
de
interlanguage-link-target

values:
interlanguage-link interwiki-eu
display: none;

values: निर्माण इस्पात – Hindi

values:
interlanguage-link interwiki-hr
display: none;

values: Құрылымдық болат – Kazakh

values:
interlanguage-link interwiki-kk
display: none;

values:
interlanguage-link interwiki-la
display: none;

values:
interlanguage-link interwiki-pl
display: none;

values: Конструкционная сталь – Russian

values:
interlanguage-link interwiki-sl
display: none;

values:
interlanguage-link interwiki-sh
display: none;

values:
interlanguage-link interwiki-fi
display: none;

values:
interlanguage-link interwiki-sv
display: none;

values: Конструкційна сталь – Ukrainian

values:
interlanguage-link interwiki-uk
display: none;

values: All languages (initial selection from common choices by you and others)

values:
suggestions
display: none; font-size: 13px;

values: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Structural_steel rootpage-Structural_steel skin-vector action-view


text:
Statement of work
From Wikipedia, the free encyclopedia
Jump to: navigation, search
This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (September 2014) (Learn how and when to remove this template message)
A statement of work (SOW) is a document routinely employed in the field of project management. It defines project-specific activities, deliverables and timelines for a vendor providing services to the client. The SOW typically also includes detailed requirements and pricing, with standard regulatory and governance terms and conditions. It is often an important accompaniment to a master service agreement or request for proposal (RFP).
Contents
[hide]
1 Overview
2 Areas addressed
3 United States government contracts
4 See also
5 Notes and references
6 External links
Overview[edit]
Many formats and styles of Statement of Work document templates have been specialized for the hardware or software solutions described in the Request for Proposal. Many companies create their own customized version of SOWs that are specialized or generalized to accommodate typical requests and proposals they receive.
Note that in many cases the Statement of Work is a binding contract.[1] Master Service Agreements or Consultant/Training Service agreements postpone certain work-specific contractual components that are addressed in individual Statements of Work. The Master Services Agreement serves as a master contract governing the terms over, potentially multiple SOWs.
Areas addressed[edit]
A statement of work typically addresses these subjects.[2][3][4]
Purpose: Why are we doing this project? A purpose statement attempts to answer this.
Scope of Work: This describes the work to be done and specifies the hardware and software involved.
Location of Work: This describes where the work is to be performed, including the location of hardware and software and where people will meet to do the work.
Period of Performance: This specifies the allowable time for projects, such as start and finish time, number of hours that can be billed per week or month, where work is to be performed and anything else that relates to scheduling.
Deliverables Schedule: This part lists and describes what is due and when.
Applicable Standards: This describes any industry specific standards that need to be adhered to in fulfilling the contract.
Acceptance Criteria: This specifies how the buyer or receiver of goods will determine if the product or service is acceptable, usually with objective criteria. See Acceptance testing.
Special Requirements: This specifies any special hardware or software, specialized workforce requirements, such as degrees or certifications for personnel, travel requirements, and anything else not covered in the contract specifics.
Type of Contract/Payment Schedule: The project acceptance will depend on if the budget available will be enough to cover the work required. Therefore a breakdown of payments by whether they are up-front or phased will usually be negotiated in an early stage.
Miscellaneous: Many items that are not part of the main negotiations may be listed because they are important to the project, and overlooking or forgetting them could pose problems for the project.
United States government contracts[edit]
For US government service contracts, the use of SOWs remains strong, although Statements of Objectives (SOOs) and Performance Work Statements (PWSs) have become increasingly popular due to their emphasis on performance-based concepts such as desired service outcomes and performance standards. SOWs are typically used when the task is well-known and can be described in specific terms. They may be preferred when the government does not desire innovative approaches or considers any deviation in contractor processes a risk. Whereas SOOs establish high-level outcomes and objectives for performance and PWSs emphasize outcomes, desired results and objectives at a more detailed and measurable level, SOWs provide explicit statements of work direction for the contractor or offeror to follow.
SOWs are typically replete with "contractor shall" statements of mandatory compliance (for example, "This task shall be performed in accordance with Agency xyz Directive, dated mm/dd/yyyy"). In practice, SOWs can also be found to contain references to desired performance outcomes, performance standards, and metrics, thus blurring their distinction between SOOs and PWSs. Aside from good practice, there is little government policy guidance that emphatically prescribes how and when to use SOWs versus SOOs or PWSs. Whereas the FAR defines PWS in Part 2 Definitions, and references SOOs and PWSs in Part 37.6 Performance Based Acquisition, SOWs are not addressed.
SOWs are usually contained in the government's solicitation (RFP or RFQ) and carried forward, as may be negotiated with the offeror, into the final contract. In federal solicitations and contracts, SOWs are inserted into Section C "Descriptions/Specifications" of the Uniform Contract Format,[5][6][7] but may also be inserted as an attachment in Section J. In task orders, the SOW may simply be included among the terms and conditions of the order itself. The SOW is often supplemented by technical reference documents and attachments. In developing the SOW, it is important to ensure that the statement of work is comprehensive and sufficiently detailed, but that the statements do not duplicate terms and conditions or other provisions elsewhere in the solicitation or contract.
Guidance in MIL-STD-881 and MIL-HDBK-245 says that a Work Breakdown Structure should be used in developing the SOW. This may use the WBS as an outline, where each WBS element (in the same name and numbering) are the sub-parts of the SOW section 3, making the development easier and to improve later billing and tracking. The WBS which focuses on intelligently dividing a hierarchy of the work elements and defining them may then have the SOW in matching sections focus on describing what will be done with that portion or how that portion will be done.
The Statement of Work should be directly linked to deliverables shown in the CDRL form. This is done by having each CDRL entry include reference to the SOW paragraph(s) that produces or uses the item, and the SOW text should be clear where it is discussing a deliverable by using the title or parenthesizing the item number (for example, "[A-001]").
See also[edit]
Contract Data Requirements List (CDRL)
Notes and references[edit]
Jump up ^ Rodney D. Stewart (1992). Proposal Preparation. p. 108. ISBN 978-0471552697. Hence, the statement of work is a document that will eventually serve as legally binding contract document that integrates and interrelates the work elements with deliverable and non-deliverable hardware, software, documentation, and services.
Jump up ^ "50 Tips for Your Statement Of Work (SOW)". NCMA Contract Manager (CM) magazine. August 2007. Retrieved 5 October 2015.
Jump up ^ "Statement of Work (SOW) Writing Guide". October 2007. Retrieved 5 October 2015.
Jump up ^ "The Elements of a Successful Statement of Work (SOW) Template". November 2011. Retrieved 5 October 2015.
Jump up ^ See Uniform Contract Format, FAR 14.2
Jump up ^ "Uniform Contract Format". dau.mil. 2008-07-14.
Jump up ^ "Uniform Contract Format". dau.mil.
External links[edit]
MIL-STD-881 series Handbook for Preparation of Statement of Work (SOW), para 2.4 links to WBS and IMP/IMS
MIL-HDBK-245 series Handbook for Preparation of Statement of Work (SOW), para 3.6.4, 3.8.1
DI-MGMT-81606 Data Item Descriptions Defining content and structure of SOW when a contractor is to provide one.
Statement of Work Writing Guide - A do-it-yourself guide to developing an RFP Statement of Work
How to write the Statement of Work
Fifty Tips for your Statement of Work, National Contract Management Association
DPAP: Statement of Work
AcqNotes: Statement of Work (SOW)
Retrieved from "https://en.wikipedia.org/w/index.php?title=Statement_of_work&oldid=795424809"
Categories:
Government procurement in the United States
Systems engineering
Hidden categories:
Articles needing additional references from September 2014
All articles needing additional references
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Article
Talk
Variants
Views
Read
Edit
View history
More
Search
Navigation
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
Languages
العربية
Deutsch
Español
Edit links
This page was last edited on 14 August 2017, at 04:11.
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
Contact Wikipedia
Developers
Cookie statement
Mobile view
Enable previews

values: mw-page-base noprint

values: mw-head-base noprint

attrs: id class style

values: firstHeading firstHeading en

values: siteSub noprint

values: jump-to-nav mw-jump

values: Help:Introduction to referencing with Wiki Markup/1

values: plainlinks metadata ambox ambox-content ambox-Refimprove

values:
/wiki/Request_for_Proposal
mw-redirect
Request for Proposal

values: Edit section: United States government contracts

values:
/wiki/Work_Breakdown_Structure
mw-redirect
Work Breakdown Structure

values:
/wiki/Contract_Data_Requirements_List
mw-redirect
Contract Data Requirements List

values:
nofollow
external text
http://www.con-tracts.com/id16.html

values:
nofollow
external text
http://www.avontisgroup.com/blog/?p=64

values:
reflist mw-references-wrap
list-style-type: decimal;

values:
/wiki/Data_Item_Descriptions
mw-redirect
Data Item Descriptions

values: Category:Government procurement in the United States

values: Category:Articles needing additional references from September 2014

values: Category:All articles needing additional references

values: Discussion about edits from this IP address [ctrl-alt-n]

values: A list of edits made from this IP address [ctrl-alt-y]

values: You are encouraged to create an account and log in; however, it is not mandatory

values: You're encouraged to log in; however, it's not mandatory. [ctrl-alt-o]

values:
/wiki/Statement_of_work
View the content page [ctrl-alt-c]
c

values: Discussion about the content page [ctrl-alt-t]

values: p-namespaces navigation vectorTabs p-namespaces-label

values:
p-variants
navigation
vectorMenu emptyPortlet
p-variants-label

values: Past revisions of this page [ctrl-alt-h]

values: p-views navigation vectorTabs p-views-label

values:
p-cactions
navigation
vectorMenu emptyPortlet
p-cactions-label

values:
mw-wiki-logo
/wiki/Main_Page
Visit the main page

values:
/wiki/Main_Page
Visit the main page [ctrl-alt-z]
z

values: Featured content – the best of Wikipedia

values: Find background information on current events

values:
/wiki/Special:Random
Load a random article [ctrl-alt-x]
x

values: portal navigation p-navigation p-navigation-label

values: Guidance on how to use and edit Wikipedia

values: About the project, what you can do, where to find things

values: A list of recent changes in the wiki [ctrl-alt-r]

values: portal navigation p-interaction p-interaction-label

values: List of all English Wikipedia pages containing links to this page [ctrl-alt-j]

values: Recent changes in pages linked from this page [ctrl-alt-k]

values:
/wiki/Wikipedia:File_Upload_Wizard
Upload files [ctrl-alt-u]
u

values: A list of all special pages [ctrl-alt-q]

values: Permanent link to this revision of the page

values: Link to connected data repository item [ctrl-alt-g]

values: Printable version of this page [ctrl-alt-p]

values:
uls-settings-trigger
Language settings
0
button
true

values: بيان العمل – Arabic

values: /static/images/wikimedia-button-1.5x.png 1.5x, /static/images/wikimedia-button-2x.png 2x

values: /static/images/poweredby_mediawiki_132x47.png 1.5x, /static/images/poweredby_mediawiki_176x62.png 2x

values: mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Statement_of_work rootpage-Statement_of_work skin-vector action-view