History of structural engineering - AbsoluteAstronomy.com

The history of structural engineering
Structural engineering
Structural engineering is a field of engineering dealing with the analysis and design of structures that support or resist loads. Structural engineering is usually considered a specialty within civil engineering, but it can also be studied in its own right....

dates back to at least 2700 BC when the step pyramid

Step pyramid

Step pyramids are structures which characterized several cultures throughout history, in several locations throughout the world. These pyramids typically are large and made of several layers of stone...

for Pharaoh

Pharaoh

Pharaoh is a title used in many modern discussions of the ancient Egyptian rulers of all periods. The title originates in the term "pr-aa" which means "great house" and describes the royal palace...

Djoser

Netjerikhet or Djoser is the best-known pharaoh of the Third dynasty of Egypt. He commissioned his official, Imhotep, to build the first of the pyramids, a step pyramid for him at Saqqara...

was built by Imhotep

Imhotep

Imhotep , fl. 27th century BC was an Egyptian polymath, who served under the Third Dynasty king Djoser as chancellor to the pharaoh and high priest of the sun god Ra at Heliopolis...

, the first engineer in history known by name. Pyramid

Pyramid

A pyramid is a structure whose outer surfaces are triangular and converge at a single point. The base of a pyramid can be trilateral, quadrilateral, or any polygon shape, meaning that a pyramid has at least three triangular surfaces...

s were the most common major structures built by ancient civilizations because it is a structural form which 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).

Another notable engineering feat from antiquity stiil in use today is the qanat water management system.
Qanat

Qanat

A qanāt is a water management system used to provide a reliable supply of water for human settlements and irrigation in hot, arid and semi-arid climates...

technology developed in the time of the Medes

Medes

The MedesThe Medes...

, the predecessors of the Persian Empire (modern-day Iran

Iran

Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...

which has the oldest and longest Qanat (older than 3000 years and longer than 71 km) that also spread to other cultures having had contact with the Persian.

Throughout ancient and medieval history most architectural design and construction was carried out by artisan

Artisan

An artisan is a skilled manual worker who makes items that may be functional or strictly decorative, including furniture, clothing, jewellery, household items, and tools...

s, such as stone mason

Masonry

Masonry is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves. The common materials of masonry construction are brick, stone, marble, granite, travertine, limestone; concrete block, glass block, stucco, and...

s and carpenter

Carpenter

A carpenter is a skilled craftsperson who works with timber to construct, install and maintain buildings, furniture, and other objects. The work, known as carpentry, may involve manual labor and work outdoors....

s, rising to the role of master builder

Master Builder

Master Builder can refer to:* Master builder, also "master mason", a central figure leading construction projects in pre-modern times .* The Master Builder, a play by Henrik Ibsen....

. 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'. Knowledge was retained by guilds and seldom supplanted by advances. Structures were repetitive, and increases in scale were incremental.

No record exists of the first calculations of the strength of structural members or the behaviour of structural material, but the profession of structural engineer only really took shape with the industrial revolution

Industrial Revolution

The Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the social, economic and cultural conditions of the times...

and the re-invention of concrete

Concrete

Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

(see History of concrete). The physical sciences underlying structural engineering began to be understood in the Renaissance

Renaissance

The Renaissance was a cultural movement that spanned roughly the 14th to the 17th century, beginning in Italy in the Late Middle Ages and later spreading to the rest of Europe. The term is also used more loosely to refer to the historical era, but since the changes of the Renaissance were not...

and have been developing ever since.

Early structural engineering developments

The recorded history of structural engineering starts with the ancient Egypt

Ancient Egypt

Ancient Egypt was an ancient civilization of Northeastern Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. Egyptian civilization coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh...

ians. In the 27th century BC, Imhotep

Imhotep

Imhotep , fl. 27th century BC was an Egyptian polymath, who served under the Third Dynasty king Djoser as chancellor to the pharaoh and high priest of the sun god Ra at Heliopolis...

was the first structural engineer known by name and constructed the first known step pyramid

Step pyramid

in Egypt. In the 26th century BC, the Great Pyramid of Giza

Great Pyramid of Giza

The Great Pyramid of Giza is the oldest and largest of the three pyramids in the Giza Necropolis bordering what is now El Giza, Egypt. It is the oldest of the Seven Wonders of the Ancient World, and the only one to remain largely intact...

was constructed in Egypt

Egypt

Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...

. It remained the largest man-made structure for millennia and was considered an unsurpassed feat in architecture

Architecture

Architecture is both the process and product of planning, designing and construction. Architectural works, in the material form of buildings, are often perceived as cultural and political symbols and as works of art...

until the 19th century AD.

The understanding of the physical laws that underpin structural engineering in the Western world

Western world

The Western world, also known as the West and the Occident , is a term referring to the countries of Western Europe , the countries of the Americas, as well all countries of Northern and Central Europe, Australia and New Zealand...

dates back to the 3rd century BC, when Archimedes

Archimedes

Archimedes of Syracuse was a Greek mathematician, physicist, engineer, inventor, and astronomer. Although few details of his life are known, he is regarded as one of the leading scientists in classical antiquity. Among his advances in physics are the foundations of hydrostatics, statics and an...

published his work On the Equilibrium of Planes in two volumes, in which he sets out the Law of the Lever, stating:
Archimedes used the principles derived to calculate the areas and centers of gravity

Center of mass

In physics, the center of mass or barycenter of a system is the average location of all of its mass. In the case of a rigid body, the position of the center of mass is fixed in relation to the body...

of various geometric figures including triangles, paraboloid

Paraboloid

In mathematics, a paraboloid is a quadric surface of special kind. There are two kinds of paraboloids: elliptic and hyperbolic. The elliptic paraboloid is shaped like an oval cup and can have a maximum or minimum point....

s, and hemispheres

Sphere

A sphere is a perfectly round geometrical object in three-dimensional space, such as the shape of a round ball. Like a circle in two dimensions, a perfect sphere is completely symmetrical around its center, with all points on the surface lying the same distance r from the center point...

. Archimedes work on this and his work on calculus and geometry, together with Euclidean geometry

Euclidean geometry

Euclidean geometry is a mathematical system attributed to the Alexandrian Greek mathematician Euclid, which he described in his textbook on geometry: the Elements. Euclid's method consists in assuming a small set of intuitively appealing axioms, and deducing many other propositions from these...

, underpin much of the mathematics and understanding of structures in modern structural engineering.

The ancient Romans

Ancient Rome

Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

made great bounds in structural engineering, pioneering large structures in masonry

Masonry

and concrete

Concrete

, many of which are still standing today. They include aqueducts, thermae

Thermae

In ancient Rome, thermae and balnea were facilities for bathing...

, columns, lighthouses, defensive walls and harbours. Their methods are recorded by Vitruvius

Vitruvius

Marcus Vitruvius Pollio was a Roman writer, architect and engineer, active in the 1st century BC. He is best known as the author of the multi-volume work De Architectura ....

in his De Architectura

De architectura

' is a treatise on architecture written by the Roman architect Vitruvius and dedicated to his patron, the emperor Caesar Augustus, as a guide for building projects...

written in 25 BC, a manual of civil and structural engineering with extensive sections on materials and machines used in construction. One reason for their success is their accurate surveying

Surveying

See Also: Public Land Survey SystemSurveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them...

techniques based on the dioptra

Dioptra

A dioptra is a classical astronomical and surveying instrument, dating from the 3rd century BCE. The dioptra was a sighting tube or, alternatively, a rod with a sight at both ends, attached to a stand...

, groma

Groma

Groma may refer to:* Groma language, spoken in SE Asia* Groma surveying, the principal Roman surveying instrument-See also:*Krama, a sturdy traditional Cambodian garment with many uses, including as a scarf...

and chorobates

Chorobates

A chorobates was a kind of level used in classical antiquity. It was composed of a wooden frame, made in the form of a beam which was fitted with a water level, and two supports at the end of the beam. It is described by Vitruvius . It is believed to be the instrument that was used to level the...

.

Centuries later, in the 15th and 16th centuries and despite lacking beam theory and calculus

Calculus

Calculus is a branch of mathematics focused on limits, functions, derivatives, integrals, and infinite series. This subject constitutes a major part of modern mathematics education. It has two major branches, differential calculus and integral calculus, which are related by the fundamental theorem...

, Leonardo da Vinci

Leonardo da Vinci

Leonardo di ser Piero da Vinci was an Italian Renaissance polymath: painter, sculptor, architect, musician, scientist, mathematician, engineer, inventor, anatomist, geologist, cartographer, botanist and writer whose genius, perhaps more than that of any other figure, epitomized the Renaissance...

produced many engineering designs based on scientific observations and rigour, including a design for a bridge to span the Bosporus

Bosporus

The Bosphorus or Bosporus , also known as the Istanbul Strait , is a strait that forms part of the boundary between Europe and Asia. It is one of the Turkish Straits, along with the Dardanelles...

. Though dismissed at the time, the design has since been judged to be both feasible and structurally valid

The foundations of modern structural engineering were laid in the 17th century by Galileo Galilei

Galileo Galilei

Galileo Galilei , was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism...

, Robert Hooke

Robert Hooke

Robert Hooke FRS was an English natural philosopher, architect and polymath.His adult life comprised three distinct periods: as a scientific inquirer lacking money; achieving great wealth and standing through his reputation for hard work and scrupulous honesty following the great fire of 1666, but...

and Isaac Newton

Isaac Newton

Sir Isaac Newton PRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian, who has been "considered by many to be the greatest and most influential scientist who ever lived."...

with the publication of three great scientific works. In 1638 Galileo published Dialogues Relating to Two New Sciences
Two New Sciences
The Discourses and Mathematical Demonstrations Relating to Two New Sciences was Galileo's final book and a sort of scientific testament covering much of his work in physics over the preceding thirty years.After his Dialogue Concerning the Two Chief World Systems, the Roman Inquisition had banned...

, outlining the sciences of the strength of materials and the motion of objects (essentially defining gravity as a force

Force

In physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...

giving rise to a constant acceleration

Acceleration

In physics, acceleration is the rate of change of velocity with time. In one dimension, acceleration is the rate at which something speeds up or slows down. However, since velocity is a vector, acceleration describes the rate of change of both the magnitude and the direction of velocity. ...

). It was the first establishment of a scientific approach to structural engineering, including the first attempts to develop a theory for beams. This is also regarded as the beginning of structural analysis, the mathematical representation and design of building structures.

This was followed in 1676 by Robert Hooke's

Robert Hooke

first statement of Hooke's Law

Hooke's law

In mechanics, and physics, Hooke's law of elasticity is an approximation that states that the extension of a spring is in direct proportion with the load applied to it. Many materials obey this law as long as the load does not exceed the material's elastic limit. Materials for which Hooke's law...

, providing a scientific understanding of elasticity of materials and their behaviour under load.

Eleven years later, in 1687, Sir Isaac Newton published Philosophiae Naturalis Principia Mathematica
Philosophiae Naturalis Principia Mathematica
Philosophiæ Naturalis Principia Mathematica, Latin for "Mathematical Principles of Natural Philosophy", often referred to as simply the Principia, is a work in three books by Sir Isaac Newton, first published 5 July 1687. Newton also published two further editions, in 1713 and 1726...

, setting out his Laws of Motion

Newton's laws of motion

Newton's laws of motion are three physical laws that form the basis for classical mechanics. They describe the relationship between the forces acting on a body and its motion due to those forces...

, providing for the first time an understanding of the fundamental laws governing structures.

Also in the 17th century, Sir Isaac Newton and Gottfried Leibniz

Gottfried Leibniz

Gottfried Wilhelm Leibniz was a German philosopher and mathematician. He wrote in different languages, primarily in Latin , French and German ....

both independently developed the Fundamental theorem of calculus

Fundamental theorem of calculus

The first part of the theorem, sometimes called the first fundamental theorem of calculus, shows that an indefinite integration can be reversed by a differentiation...

, providing one of the most important mathematical tools in engineering.

Further advances in the mathematics needed to allow structural engineers to apply the understanding of structures gained through the work of Galileo, Hooke and Newton during the 17th century came in the 18th century when Leonhard Euler

Leonhard Euler

Leonhard Euler was a pioneering Swiss mathematician and physicist. He made important discoveries in fields as diverse as infinitesimal calculus and graph theory. He also introduced much of the modern mathematical terminology and notation, particularly for mathematical analysis, such as the notion...

pioneered much of the mathematics and many of the methods which allow structural engineers to model and analyse structures. Specifically, he developed the Euler-Bernoulli beam equation

Euler-Bernoulli beam equation

Euler–Bernoulli beam theory is a simplification of the linear theory of elasticity which provides a means of calculating the load-carrying and deflection characteristics of beams. It covers the case for small deflections of a beam which is subjected to lateral loads only...

with Daniel Bernoulli

Daniel Bernoulli

Daniel Bernoulli was a Dutch-Swiss mathematician and was one of the many prominent mathematicians in the Bernoulli family. He is particularly remembered for his applications of mathematics to mechanics, especially fluid mechanics, and for his pioneering work in probability and statistics...

(1700–1782) circa 1750 - the fundamental theory underlying most structural engineering design.

Daniel Bernoulli

Daniel Bernoulli

, with Johann (Jean) Bernoulli (1667–1748), is also credited with formulating the theory of virtual work

Virtual work

Virtual work arises in the application of the principle of least action to the study of forces and movement of a mechanical system. Historically, virtual work and the associated calculus of variations were formulated to analyze systems of rigid bodies, but they have also been developed for the...

, providing a tool using equilibrium of forces and compatibility of geometry to solve structural problems. In 1717 Jean Bernoulli wrote to Pierre Varignon

Pierre Varignon

Pierre Varignon was a French mathematician. He was educated at the Jesuit College and the University in Caen, where he received his M.A. in 1682. He took Holy Orders the following year....

explaining the principle of virtual work, while in 1726 Daniel Bernoulli wrote of the "composition of forces".

In 1757 Leonhard Euler

Leonhard Euler

went on to derive the Euler buckling

Buckling

In science, buckling is a mathematical instability, leading to a failure mode.Theoretically, buckling is caused by a bifurcation in the solution to the equations of static equilibrium...

formula, greatly advancing the ability of engineers to design compression elements.

Modern developments in structural engineering

Throughout the late 19th and early 20th centuries, materials science and structural analysis underwent development at a tremendous pace.

Though elasticity was understood in theory well before the 19th century, it was not until 1821 that Claude-Louis Navier

Claude-Louis Navier

Claude-Louis Navier born Claude Louis Marie Henri Navier , was a French engineer and physicist who specialized in mechanics.The Navier–Stokes equations are named after him and George Gabriel Stokes....

formulated the general theory of elasticity in a mathematically usable form. In his leçons of 1826 he explored a great range of different structural theory, and was the first to highlight that the role of a structural engineer is not to understand the final, failed state of a structure, but to prevent that failure in the first place. In 1826 he also established the elastic modulus

Elastic modulus

An elastic modulus, or modulus of elasticity, is the mathematical description of an object or substance's tendency to be deformed elastically when a force is applied to it...

as a property of materials independent of the second moment of area

Second moment of area

The second moment of area, also known as the area moment of inertia, moment of inertia of plane area, or second moment of inertia is a property of a cross section that can be used to predict the resistance of beams to bending and deflection, around an axis that lies in the cross-sectional plane...

, allowing engineers for the first time to both understand structural behaviour and structural materials.

Towards the end of the 19th century, in 1873, Carlo Alberto Castigliano presented his dissertation "Intorno ai sistemi elastici", which contains his theorem for computing displacement as partial derivative of the strain energy.

In 1824, Portland cement

Portland cement

Portland cement is the most common type of cement in general use around the world because it is a basic ingredient of concrete, mortar, stucco and most non-specialty grout...

was patented by the engineer Joseph Aspdin

Joseph Aspdin

Joseph Aspdin was a British cement manufacturer who obtained the patent for Portland cement on 21 October 1824....

as "a superior cement resembling Portland Stone", British Patent no. 5022. Although different forms of cement already existed (Pozzolanic cement was used by the Romans as early as 100 B.C. and even earlier by the ancient Greek and Chinese civilizations) and were in common usage in Europe from the 1750s, the discovery made by Aspdin used commonly available, cheap materials, making concrete construction an economical possibility.

Developments in concrete continued with the construction in 1848 of a rowing boat built of ferrocement

Ferrocement

The term ferrocement is most commonly applied to a mixture of Portland cement and sand reinforced with layers of woven or expanded steel mesh and closely spaced small-diameter steel rods rebar. It can be used to form relatively thin, compound curved sheets to make hulls for boats, shell roofs,...

- the forerunner of modern reinforced concrete

Reinforced concrete

Reinforced concrete is concrete in which reinforcement bars , reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. It was invented by French gardener Joseph Monier in 1849 and patented in 1867. The term Ferro Concrete refers only to concrete that is...

- by Joseph-Louis Lambot

Joseph-Louis Lambot

Joseph-Louis Lambot , is the inventor of ferro-cement, which led to the development of what is now known as reinforced concrete...

. He patented his system of mesh reinforcement and concrete in 1855, one year after W.B. Wilkinson also patented a similar system. This was followed in 1867 when a reinforced concrete planting tub was patented by Joseph Monier

Joseph Monier

-Overview:Joseph Monier was a French gardener and one of the principal inventors of reinforced concrete....

in Paris, using steel mesh reinforcement similar to that used by Lambot and Wilkinson. Monier took the idea forward, filing several patents for tubs, slabs and beams, leading eventually to the Monier system of reinforced structures, the first use of steel reinforcement bars located in areas of tension in the structure.

Steel construction was first made possible in the 1850s when Henry Bessemer

Henry Bessemer

Sir Henry Bessemer was an English engineer, inventor, and businessman. Bessemer's name is chiefly known in connection with the Bessemer process for the manufacture of steel.-Anthony Bessemer:...

developed the Bessemer process

Bessemer process

The Bessemer process was the first inexpensive industrial process for the mass-production of steel from molten pig iron. The process is named after its inventor, Henry Bessemer, who took out a patent on the process in 1855. The process was independently discovered in 1851 by William Kelly...

to produce steel

Steel

Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

. He gained patents for the process in 1855 and 1856 and successfully completed the conversion of cast iron into cast steel in 1858. Eventually mild steel would replace both wrought iron

Wrought iron

thumb|The [[Eiffel tower]] is constructed from [[puddle iron]], a form of wrought ironWrought iron is an iron alloy with a very low carbon...

and cast iron

Cast iron

Cast iron is derived from pig iron, and while it usually refers to gray iron, it also identifies a large group of ferrous alloys which solidify with a eutectic. The color of a fractured surface can be used to identify an alloy. White cast iron is named after its white surface when fractured, due...

as the preferred metal for construction.

During the late 19th century, great advancements were made in the use of cast iron, gradually replacing wrought iron as a material of choice. Ditherington Flax Mill

Ditherington Flax Mill

Ditherington Flax Mill , located in Ditherington, a suburb of Shrewsbury, England, is the oldest iron framed building in the world. As such, it is seen as the "grandfather of skyscrapers", despite being only as tall as a modern five-story building. Its importance was officially recognised in the...

in Shrewsbury

Shrewsbury

Shrewsbury is the county town of Shropshire, in the West Midlands region of England. Lying on the River Severn, it is a civil parish home to some 70,000 inhabitants, and is the primary settlement and headquarters of Shropshire Council...

, designed by Charles Bage

Charles Bage

Charles Woolley Bage was an English architect, born in Derby, Derbyshire, in the United Kingdom. He was the designer of the first ever iron framed building, the Ditherington Flax Mill, located in the outskirts of Shrewsbury town centre, built between 1796 and 1797.Shortly after his birth, his...

, was the first building in the world with an interior iron frame. It was built in 1797. In 1792 William Strutt

William Strutt (inventor)

William Strutt FRS, was a cotton spinner in Belper, England.-Biography:Strutt was the first son of Jedediah Strutt and, after a good education, joined his father's business at the age of fourteen...

had attempted to build a fireproof mill at Belper in Derby

Derby

Derby , is a city and unitary authority in the East Midlands region of England. It lies upon the banks of the River Derwent and is located in the south of the ceremonial county of Derbyshire. In the 2001 census, the population of the city was 233,700, whilst that of the Derby Urban Area was 229,407...

(Belper West Mill), using cast iron columns and timber beams within the depths of brick arches that formed the floors. The exposed beam soffits were protected against fire by plaster. This mill at Belper was the world's first attempt to construct fireproof buildings, and is the first example of fire engineering. This was later improved upon with the construction of Belper North Mill

Belper North Mill

Belper North Mill, also known as Strutt's North Mill, Belper, is one of the Derwent Valley Mills designated UNESCO World Heritage Status in 2001.It is sited in Belper, a town in Derbyshire, England roughly half way between Derby and Matlock....

, a collaboration between Strutt and Bage, which by using a full cast iron frame represented the world's first "fire proofed" building.

The Forth Bridge was built by Benjamin Baker, Sir John Fowler and William Arrol

William Arrol

Sir William Arrol was a Scottish civil engineer, bridge builder, and Liberal Party politician.The son of a spinner, he was born in Houston, Renfrewshire, and started work in a cotton mill at only 9 years of age. He started training as a blacksmith by age 13, and went on to learn mechanics and...

in 1889, using steel

Steel

, after the original design for the bridge by Thomas Bouch

Thomas Bouch

Sir Thomas Bouch was a British railway engineer in Victorian Britain.He was born in Thursby, near Carlisle, Cumberland, England and lived in Edinburgh. He helped develop the caisson and the roll-on/roll-off train ferry. He worked initially for the North British Railway and helped design parts of...

was rejected following the collapse of his Tay Rail Bridge

Tay Rail Bridge

The Tay Bridge is a railway bridge approximately two and a quarter miles long that spans the Firth of Tay in Scotland, between the city of Dundee and the suburb of Wormit in Fife ....

. The Forth Bridge was one of the first major uses of steel, and a landmark in bridge design. Also in 1889, the wrought-iron Eiffel Tower

Eiffel Tower

The Eiffel Tower is a puddle iron lattice tower located on the Champ de Mars in Paris. Built in 1889, it has become both a global icon of France and one of the most recognizable structures in the world...

was built by Gustave Eiffel and Maurice Koechlin, demonstrating the potential of construction using iron, despite the fact that steel construction was already being used elsewhere.

During the late 19th century, Russian structural engineer Vladimir Shukhov

Vladimir Shukhov

Vladimir Grigoryevich Shukhov , was a Russian engineer-polymath, scientist and architect renowned for his pioneering works on new methods of analysis for structural engineering that led to breakthroughs in industrial design of world's first hyperboloid structures, lattice shell structures, tensile...

developed analysis methods for tensile structure

Tensile structure

A tensile structure is a construction of elements carrying only tension and no compression or bending. The term tensile should not be confused with tensegrity, which is a structural form with both tension and compression elements....

s, thin-shell structure

Thin-shell structure

Thin-shell structures are light weight constructions using shell elements. These elements are typically curved and are assembled to large structures...

s, lattice shell structure

Gridshell

A gridshell is a structure which derives its strength from its double curvature , but is constructed of a grid or lattice....

s and new structural geometries such as hyperboloid structure

Hyperboloid structure

Hyperboloid structures are architectural structures designed with hyperboloid geometry. Often these are tall structures such as towers where the hyperboloid geometry's structural strength is used to support an object high off the ground, but hyperboloid geometry is also often used for decorative...

s. Pipeline transport

Pipeline transport

Pipeline transport is the transportation of goods through a pipe. Most commonly, liquids and gases are sent, but pneumatic tubes that transport solid capsules using compressed air are also used....

was pioneered by Vladimir Shukhov

Vladimir Shukhov

and the Branobel

Branobel

The Petroleum Production Company Nobel Brothers, Limited,or Branobel , was an oil company set up by Ludvig Nobel and Baron Peter von Bilderling, in Baku, Azerbaijan...

company in the late 19th century.

Again taking reinforced concrete design forwards, from 1892 onwards François Hennebique

François Hennebique

François Hennebique was a French engineer and self-educated builder who patented his pioneering reinforced-concrete construction system in 1892, integrating separate elements of construction, such as the column and the beam, into a single monolithic element...

's firm used his patented reinforced concrete system to build thousands of structures throughout Europe. Thaddeus Hyatt in the US and Wayss & Freitag in Germany also patented systems. The firm AG für Monierbauten constructed 200 reinforced concrete bridges in Germany between 1890 and 1897 The great pioneering uses of reinforced concrete however came during the first third of the 20th century, with Robert Maillart

Robert Maillart

Robert Maillart was a Swiss civil engineer who revolutionized the use of structural reinforced concrete with such designs as the three-hinged arch and the deck-stiffened arch for bridges, and the beamless floor slab and mushroom ceiling for industrial buildings...

and others furthering of the understanding of its behaviour. Maillart noticed that many concrete bridge structures were significantly cracked, and as a result left the cracked areas out of his next bridge design - correctly believing that if the concrete was cracked, it was not contributing to the strength. This resulted in the revolutionary Salginatobel Bridge

Salginatobel Bridge

Salginatobel Bridge is a reinforced concrete arch bridge designed by renowned Swiss civil engineer Robert Maillart. It was constructed across an alpine valley in Schiers, Switzerland between 1929 and 1930...

design. Wilhelm Ritter formulated the truss theory for the shear design of reinforced concrete beams in 1899, and Emil Mörsch improved this in 1902. He went on to demonstrate that treating concrete in compression as a linear-elastic material was a conservative approximation of its behaviour. Concrete design and analysis has been progressing ever since, with the development of analysis methods such as yield line theory, based on plastic analysis of concrete (as opposed to linear-elastic), and many different variations on the model for stress distributions in concrete in compression

Prestressed concrete

Prestressed concrete

Prestressed concrete is a method for overcoming concrete's natural weakness in tension. It can be used to produce beams, floors or bridges with a longer span than is practical with ordinary reinforced concrete...

, pioneered by Eugène Freyssinet

Eugène Freyssinet

Eugène Freyssinet was a French structural and civil engineer. He was the major pioneer of prestressed concrete.Freyssinet was born in at Objat, Corrèze, France. He worked in the École Nationale des Ponts et Chaussées in Paris, France where he designed several bridges until the First World War...

with a patent in 1928, gave a novel approach in overcoming the weakness of concrete structures in tension. Freyssinet constructed an experimental prestressed arch in 1908 and later used the technology in a limited form in the Plougastel Bridge

Plougastel Bridge

The Plougastel Bridge, or Albert-Louppe Bridge, is a bridge over the Elorn River near Brest, France, connecting Plougastel-Daoulas and Le Relecq-Kerhuon....

in France in 1930. He went on to build six prestressed concrete bridges across the Marne River

Marne River

The Marne is a river in France, a right tributary of the Seine in the area east and southeast of Paris. It is long. The river gave its name to the départements of Haute-Marne, Marne, Seine-et-Marne, and Val-de-Marne....

, firmly establishing the technology.

Structural engineering theory was again advanced in 1930 when Professor Hardy Cross

Hardy Cross

Hardy Cross, 1885–1959, born in Nansemond County, Virginia, was a U.S. structural engineer and the developer of the moment distribution method for structural calculation of large buildings. The method was in general use from c.1935 until c.1960 when it was gradually superseded by other methods...

developed his Moment distribution method

Moment distribution method

The moment distribution method is a structural analysis method for statically indeterminate beams and frames developed by Hardy Cross. It was published in 1930 in an ASCE journal. The method only accounts for flexural effects and ignores axial and shear effects...

, allowing the real stresses of many complex structures to be approximated quickly and accurately.

In the mid 20th century John Fleetwood Baker went on to develop the plasticity theory of structures, providing a powerful tool for the safe design of steel structures.

High-rise construction, though possible from the late 19th century onwards, was greatly advanced during the second half of the 20th century. Fazlur Khan

Fazlur Khan

Fazlur Rahman Khan was a Bangladeshi born architect and structural engineer. He is a central figure behind the "Second Chicago School" of architecture, and is regarded as the "Father of tubular design for high-rises"...

designed structural systems that remain fundamental to many modern high rise construction

Skyscraper

A skyscraper is a tall, continuously habitable building of many stories, often designed for office and commercial use. There is no official definition or height above which a building may be classified as a skyscraper...

s and which he employed in his structural designs for the John Hancock Center

John Hancock Center

John Hancock Center at 875 North Michigan Avenue in the Streeterville area of Chicago, Illinois, is a 100-story, 1,127-foot tall skyscraper, constructed under the supervision of Skidmore, Owings and Merrill, with chief designer Bruce Graham and structural engineer Fazlur Khan...

in 1969 and Sears Tower

Sears Tower

Sears' optimistic growth projections were not met. Competition from its traditional rivals continued, with new competition by retailing giants such as Kmart, Kohl's, and Wal-Mart. The fortunes of Sears & Roebuck declined in the 1970s as the company lost market share; its management grew more...

in 1973. Khan's central innovation in skyscraper design and construction

Skyscraper design and construction

The design and construction of skyscrapers involves creating safe, habitable spaces in very tall buildings. The buildings must support their weight, resist wind and earthquakes, and protect occupants from fire. Yet they must also be conveniently accessible, even on the upper floors, and provide...

was the idea of the "tube" and "bundled tube"

Tube (structure)

In structural engineering, the tube is the name given to the systems where in order to resist lateral loads a building is designed to act like a three-dimensional hollow tube, cantilevered perpendicular to the ground. The system was introduced by Fazlur Rahman Khan while at Skidmore, Owings and...

structural systems for tall buildings. He defined the framed tube structure as "a three dimensional space structure composed of three, four, or possibly more frames, braced frames, or shear walls, joined at or near their edges to form a vertical tube-like structural system capable of resisting lateral forces in any direction by cantilevering from the foundation." Closely spaced interconnected exterior columns form the tube. Horizontal loads, for example wind, are supported by the structure as a whole. About half the exterior surface is available for windows. Framed tubes allow fewer interior columns, and so create more usable floor space. Where larger openings like garage doors are required, the tube frame must be interrupted, with transfer girders used to maintain structural integrity. The first building to apply the tube-frame construction was in the DeWitt-Chestnut Apartment Building which Khan designed in Chicago

Chicago

Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...

. This laid the foundations for the tube structures used in most later skyscraper constructions, including the construction of the World Trade Center

Construction of the World Trade Center

The construction of the World Trade Center was conceived as an urban renewal project, spearheaded by David Rockefeller, to help revitalize Lower Manhattan. The project was developed by the Port Authority of New York and New Jersey, which hired architect Minoru Yamasaki who came up with the specific...

.

Another innovation that Fazlur Khan developed was the concept of X-bracing, which reduced the lateral load on the building by transferring the load into the exterior columns. This allowed for a reduced need for interior columns thus creating more floor space, and can be seen in the John Hancock Center. The first sky lobby was also designed by Khan for the John Hancock Center in 1969. Later buildings with sky lobbies include the World Trade Center

World Trade Center

The original World Trade Center was a complex with seven buildings featuring landmark twin towers in Lower Manhattan, New York City, United States. The complex opened on April 4, 1973, and was destroyed in 2001 during the September 11 attacks. The site is currently being rebuilt with five new...

, Petronas Twin Towers

Petronas Twin Towers

The Petronas Towers are skyscrapers and twin towers in Kuala Lumpur, Malaysia...

and Taipei 101

Taipei 101

Taipei 101 , formerly known as the Taipei World Financial Center, is a landmark skyscraper located in Xinyi District, Taipei, Taiwan. The building ranked officially as the world's tallest from 2004 until the opening of the Burj Khalifa in Dubai in 2010...

.

In 1987 Jörg Schlaich

Jörg Schlaich

Prof. Dr.-Ing. Drs. h.c. Jörg Schlaich is a German structural engineer. He later founded his own firm Schlaich Bergermann & Partner.-Early career:...

and Kurt Schafer published the culmination of almost ten years of work on the strut and tie method for concrete analysis - a tool to design structures with discontinuities such as corners and joints, providing another powerful tool for the analysis of complex concrete geometries.

In the late 20th and early 21st centuries the development of powerful computers has allowed finite element analysis to become a significant tool for structural analysis and design. The development of finite element programs has led to the ability to accurately predict the stresses in complex structures, and allowed great advances in structural engineering design and architecture. In the 1960s and 70s computational analysis was used in a significant way for the first time on the design of the Sydney Opera House

Sydney Opera House

The Sydney Opera House is a multi-venue performing arts centre in the Australian city of Sydney. It was conceived and largely built by Danish architect Jørn Utzon, finally opening in 1973 after a long gestation starting with his competition-winning design in 1957...

roof. Many modern structures could not be understood and designed without the use of computational analysis.

Developments in the understanding of materials and structural behaviour in the latter part of the 20th century have been significant, with detailed understanding being developed of topics such as fracture mechanics

Fracture mechanics

Fracture mechanics is the field of mechanics concerned with the study of the propagation of cracks in materials. It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechanics to characterize the material's resistance to fracture.In...

, earthquake engineering

Earthquake engineering

Earthquake engineering is the scientific field concerned with protecting society, the natural and the man-made environment from earthquakes by limiting the seismic risk to socio-economically acceptable levels...

, composite materials, temperature effects on materials, dynamics and vibration control

Vibration control

In earthquake engineering, vibration control is a set of technical means aimed to mitigate seismic impacts in building and non-building structures.All seismic vibration control devices may be classified as passive, active or hybrid where:...

, fatigue

Fatigue (material)

'In materials science, fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading. The nominal maximum stress values are less than the ultimate tensile stress limit, and may be below the yield stress limit of the material.Fatigue occurs...

, creep

Creep (deformation)

In materials science, creep is the tendency of a solid material to slowly move or deform permanently under the influence of stresses. It occurs as a result of long term exposure to high levels of stress that are below the yield strength of the material....

and others. The depth and breadth of knowledge now available in structural engineering

Structural engineering

Structural engineering is a field of engineering dealing with the analysis and design of structures that support or resist loads. Structural engineering is usually considered a specialty within civil engineering, but it can also be studied in its own right....

, and the increasing range of different structures and the increasing complexity of those structures has led to increasing specialisation of structural engineers.