History
El arco se popularizó en la época romana y se extendió principalmente con la influencia europea, aunque ya era conocido y ocasionalmente utilizado desde antes. Muchas arquitecturas antiguas evitaron el uso de arcos, incluidas las vikingas e hindúes.[12].
El arco posee en la historia de la construcción un periodo de seis mil años.[13] Aparece por primera vez en la arquitectura de Mesopotamia y se transmite a Europa, mediante su uso en el Imperio romano, hasta alcanzar su máximo esplendor en el siglo .[14] Esto se produce debido a la intuición básica de los constructores medievales, que sin conocer la teoría del arco, construyen catedrales y puentes que permanecen edificados hasta hoy en día.[15] La historia se puede decir que pasa por tres etapas, una primera en la que se elaboran arcos siguiendo la intuición y experiencia de los constructores, otra en la que se abstaren propiedades empíricas en modelos geométricos (algunos de ellos sin inspiración científica) y una tercera en la que los modernos modelos analíticos permiten saber cómo 'funciona un arco'.
intuitive period
In nature, arches appear naturally, either those that form spontaneously in the passage of a mountain, which, due to the collapse of stones, are arranged in a stable isostatic arrangement of an arch. Or, in the cavities of the ground, which, due to the erosion of various agents (such as wind and water), form arch-shaped openings. All these spontaneous arches, formed in nature, were perhaps the inspiration for the first men who placed stones imitating their curved arrangement. The arches had magical meanings due to their ability to stand 'on their own'; in some cultures the large arches of bridges were attributed to the work of the devil.[16] The habitual use of arches in the constructions used in some cultures left the first steps of empirical knowledge that would later be developed into geometric laws. Many of the ancient treatises show this knowledge about the construction of arches through the use of geometric drawings.
Empirical development
The bow appeared in Mesopotamia, and in the Indus Valley culture. It was used in Ancient Egypt, Assyria, Etruria and later in Ancient Rome. The ancient Romans learned the semicircular arch from the Etruscans (both cultures apparently independently adopted the design in the century BC), perfected it, and were the first builders in Europe to harness its full potential for above-ground buildings. The Romans were the first builders in Europe, and perhaps the first in the world, to fully appreciate the advantages of the arch, vault and dome. [17].
The arch was used in auxiliary buildings, underground and drainage structures; The Romans were the first to use them in monumental buildings, although it was thought that Roman architects learned their use from the Etruscans. The so-called Roman arch is semicircular in shape and built from an odd number of voussoirs, so that there is a central voussoir or key "Key (architecture)"). The Romans used this type of semicircular arch in many of their traditional structures, such as aqueducts, palaces, and amphitheatres. This Roman semicircular arch was considered by later architects (until the 19th century) as the most stable of the arches.[18] An example of empirical construction was the popular "rule of the third" that in semicircular arches it was enough to size a stirrup with the thickness of one third of its opening.
In the Middle Ages, the use of the arch with stone voussoirs reached a high technical development in the construction of cathedrals; It is still used today in some structures such as bridges,[8] although with various materials. In the century, Gothic architecture began to use a type of pointed arch that learned from previous experiences: in Romanesque structures they observed that the semicircular arches were not very perfect, since some failed due to the kidneys (middle part of each semi-arch), so they looked for an arch in which the kidneys were less protruding, which resulted in the pointed arch. The rules for building arches are found in the verbal tradition of the Gothic stonemasons' lodges. In many cases these rules were complex to understand and few of these rules have come directly from writings to the present day.[19] In some treaties the size of the abutments is described by drawings of hexagons inscribed on the arch. This method was very popular and gave successful results.
In Spain there were theorists who developed ideas about their construction in the 19th century, among them Rodrigo Gil de Hontañón and later Tomás Vicente Tosca stand out.[20] However, the emergence of the analysis of vaulted factory structures occurred at the end of the 19th century. It can be stated that in the second half of the century, the stability of the factory-built arch was already sufficiently resolved for practical purposes and there were various sufficiently developed methods and published tables of relatively simple use. The Italian physicist Galileo Galilei was one of the first to find out that the empirical foundations in the design of arches could have a physical cause,[21] showing that the theory of the arch could be explained by the laws of statics "Statics (mechanics)").
Scientific theories
The attribution of being the first to determine a theory about how an arch works falls on Leonardo da Vinci, but until 1670, the problem was not formulated in scientific terms, by the physicist Robert Hooke who mentions at the end of one of his books, in the form of an anagram, how the arch resembles the inverted catenary. The deciphered anagram read in Latin:
Robert Hooke mentions this conclusion, just after having collaborated with Christopher Wren in the construction of the Dome of St. Paul's Cathedral. You realize that an arch is supported if an inverted catenary is contained in its thickness. In the same way, years later, the mathematician Greqory provided a way to size a stirrup, demonstrating that if in the catenary the forces push inwards, in the arc of an inverted catenary they do so outwards. The French mathematician Philippe de la Hire makes a different approach in his Traite de Mécanique trying to find out what is the appropriate weight of the voussoirs in order to improve the stability of the arch.[22] Using for the first time a funicular polygon in the description of an arch, with the initial hypothesis of there being no resistance between the voussoirs. Later, in 1712, he published his memoir Sur la construction des voütes dans les edifices, which influenced later generations of European builders, such as the construction tables of bridge arches prepared by Perronet.[23] Popular tables in the empirical construction of European bridges until the middle of the century. In the last quarter of the century, with the arrival of the industrial revolution, some examples of continuous arches made of cast iron appeared. One of the first is a bridge arch built in 1779, and called Iron Bridge that crosses the River Severn (United Kingdom) "River Severn (United Kingdom)") with thirty meters of span.[24] Cast iron paves the way for the later use, already in the 19th century, of iron and with this the span of the bridges is considerably increased. Poncelet was one of the first to verify that arches were hyperstatic (or redundant) structures whose solution requires the solution of compatibility equations and a law that relates deformations to stresses.
The engineer Pierre Couplet, following a different hypothesis than Hire's, analytically managed to find a minimum value for the thickness of an arch.[14] Below that value the arch collapses. The most subsequently used description of the stability of an arch was made by Coulomb in 1773.[25] In his work he shows seven possible ways to collapse an arch. Between 1830 and 1840, the theory of the thrust line was developed simultaneously by various research engineers. One of them is H. Moseley who describes the stability of an arch.[26] Results that were perfected by Jules Carvallo,[27] and Durand-Claye. The research carried out with the new theories, verifying the efficiency of the old empirical methods, shows that despite being basically incorrect, the constructive results were so surprisingly good.[28].