Editing Structural engineering (section)

==History==
{{Main|History of structural engineering}}
[[File:Pont du Gard BLS.jpg|thumb|[[Pont du Gard]], France, a [[Ancient Rome|Roman]] era aqueduct circa 19 BC]]

Structural engineering dates back to 2700 B.C. when the step pyramid for Pharaoh [[Djoser]] was built by [[Imhotep]], the first engineer in history known by name. Pyramids were the most common major structures built by ancient civilizations because the structural form of a pyramid is inherently stable and can be almost infinitely scaled (as opposed to most other structural forms, which cannot be linearly increased in size in proportion to increased loads).<ref name = Saouma/>

The structural stability of the pyramid, whilst primarily gained from its shape, relies also on the strength of the stone from which it is constructed, and its ability to support the weight of the stone above it.<ref name=Fonte>{{cite report|title=Building the Great Pyramid in a Year: An Engineer's Report |author=Fonte, Gerard C. A.|publisher=Algora Publishing: New York|pages=34}}CV</ref> The limestone blocks were often taken from a quarry near the building site and have a compressive strength from 30 to 250 MPa (MPa = Pa × 10<sup>6</sup>).<ref>{{cite web|url=http://www.stanford.edu/~tyzhu/Documents/Some%20Useful%20Numbers.pdf|title=Some Useful Numbers on the Engineering Properties of Materials (Geologic and Otherwise)|publisher=Stanford University|access-date=2013-12-05|url-status=dead|archive-url=https://web.archive.org/web/20120616163119/http://www.stanford.edu/~tyzhu/Documents/Some%20Useful%20Numbers.pdf|archive-date=2012-06-16}}</ref> Therefore, the structural strength of the pyramid stems from the material properties of the stones from which it was built rather than the pyramid's geometry.

Throughout ancient and medieval history most architectural design and construction were carried out by artisans, such as stonemasons and carpenters, rising to the role of master builder. No theory of structures existed, and understanding of how structures stood up was extremely limited, and based almost entirely on empirical evidence of 'what had worked before' and [[intuition]]. Knowledge was retained by guilds and seldom supplanted by advances. Structures were repetitive, and increases in scale were incremental.<ref name=Saouma>{{cite web|url=http://ceae.colorado.edu/~saouma/Lecture-Notes/se.pdf|title=Lecture notes in Structural Engineering|author=Victor E. Saouma|publisher=University of Colorado|access-date=2007-11-02|url-status=dead|archive-url=https://web.archive.org/web/20180413110017/http://ceae.colorado.edu/~saouma/Lecture-Notes/se.pdf|archive-date=2018-04-13}}</ref>

No record exists of the first calculations of the strength of structural members or the behavior of structural material, but the profession of a structural engineer only really took shape with the Industrial Revolution and the re-invention of concrete (see [[Concrete#History|History of Concrete]]). The physical sciences underlying structural engineering began to be understood in the Renaissance and have since developed into computer-based applications pioneered in the 1970s.<ref>{{cite web |url=http://www.structuremag.org/downloads/pulse-release-ETABS-receives-Top-Seismic-product-5-24-06.pdf |title=ETABS receives "Top Seismic Product of the 20th Century" Award |year=2006 |work=Press Release |publisher=Structure Magazine |access-date=April 20, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20121127130531/http://www.structuremag.org/downloads/pulse-release-ETABS-receives-Top-Seismic-product-5-24-06.pdf |archive-date=November 27, 2012 }}</ref>

===Timeline===
[[File:Galileo Galilei by Ottavio Leoni Marucelliana (cropped).jpg|thumb|upright| [[Galileo Galilei]] published the book ''[[Two New Sciences]]'' in which he examined the failure of simple structures.]]
[[File:Sir Isaac Newton by Sir Godfrey Kneller, Bt.jpg|thumb|upright| [[Isaac Newton]] published ''[[Philosophiae Naturalis Principia Mathematica]]'', which contains his [[Newton's laws of motion|laws of motion]].]]
[[File:Leonhard Euler 2.jpg|thumb|upright| [[Leonhard Euler]] developed the theory of [[buckling]] of columns.]]
* 1452–1519 [[Leonardo da Vinci]] made many contributions.
* 1638: [[Galileo Galilei]] published the book ''[[Two New Sciences]]'' in which he examined the failure of simple structures.
* 1660: [[Hooke's law]] by [[Robert Hooke]].
* 1687: [[Isaac Newton]] published ''[[Philosophiæ Naturalis Principia Mathematica]]'', which contains his [[Newton's laws of motion|laws of motion]].
* 1750: [[Euler–Bernoulli beam equation]].
* 1700–1782: [[Daniel Bernoulli]] introduced the principle of [[virtual work]].
* 1707–1783: [[Leonhard Euler]] developed the theory of [[buckling]] of columns.
* 1826: [[Claude-Louis Navier]] published a treatise on the elastic behaviors of structures.
* 1873: [[Carlo Alberto Castigliano]] presented his dissertation "Intorno ai sistemi elastici", which contains [[Castigliano's method|his theorem]] for computing displacement as the partial derivative of the strain energy. This theorem includes the method of "least work" as a special case.
* 1874: [[Otto Mohr]] formalized the idea of a statically indeterminate structure.
* 1922: [[Stephen Timoshenko|Timoshenko]] corrects the [[Euler–Bernoulli beam theory|Euler–Bernoulli beam equation]].
* 1936: [[Hardy Cross]]' publication of the moment distribution method, an important innovation in the design of continuous frames.
* 1941: [[Alexander Hrennikoff]] solved the discretization of plane elasticity problems using a lattice framework.
* 1942: [[Richard Courant]] divided a domain into finite subregions.
* 1956: J. Turner, R. W. Clough, H. C. Martin, and L. J. Topp's paper on the "Stiffness and Deflection of Complex Structures" introduces the name "[[finite-element method]]" and is widely recognized as the first comprehensive treatment of the method as it is known today.

===Structural failure===
{{Main|Structural failure|List of structural failures and collapses}}

The history of structural engineering contains many collapses and failures.  Sometimes this is due to obvious negligence, as in the case of the [[2008 Pétion-ville school collapse|Pétion-Ville school collapse]], in which Rev. Fortin Augustin ''" constructed the building all by himself, saying he didn't need an engineer as he had good knowledge of construction"'' following a partial collapse of the three-story schoolhouse that sent neighbors fleeing. The final collapse killed 94 people, mostly children.

In other cases [[crash testing|structural failures]] require careful study, and the results of these inquiries have resulted in improved practices and a greater understanding of the science of structural engineering.  Some such studies are the result of [[forensic engineering]] investigations where the original engineer seems to have done everything in accordance with the state of the profession and acceptable practice yet a failure still eventuated.  A famous case of structural knowledge and practice being advanced in this manner can be found in a series of failures involving [[box girders]] which collapsed in Australia during the 1970s.