If you have ever stood in a building and looked at a curved ceiling, you may have seen cross vaults. In the Romanesque churches in the first millennium AD, architects built a roof of wood or stone with a simpler structure. But the wooden roofs always lit up and burned the entire building. And with a cylindrical vault, it was so heavy that the walls had to be very thick. Place in them remained only for a few tiny windows. As a result, the church looked dark.
The emergence of a new design
Scientists believe that the style developed in Rome and gradually spread to Byzantine and Islamic architecture. At that time, a cylindrical vault was more common. But the Romans began developing a new type for applications in various structures, some with a significant span. The first cross vault appeared in Europe, but was built in Delphi by the Pergamon king Attalos I between 241 and 197. BC e. They were used in extensive rooms, such as frigidaria in the baths of Caracalla and Diocletian.
The Impact of Temple Construction
Gradually, a new direction became very influential in the church architecture of the Middle Ages. The desire to build temples reached its climax, and the new type was aggressively introduced because of its ability to create a support without massive support formations. In addition, he provided church architects with the opportunity to avoid the dim lighting inherent in the previous design, which required a large mass in order to maintain sufficient strength.
Design features
Since 1050 g. e. architects have already actively used such arches. When you look at the Romanesque cross vault, you see four curved surfaces that are found in the center. They consist of two cylindrical, which intersect each other, forming the letter X. In order to make such a design, builders crossed more familiar forms in the middle at a perpendicular or right angle. Where the edges of the arches meet, they create clear lines. They are also known as ribs. Compared to cylindrical, the cross vault in architecture provides good material and labor savings.
The spread of architectural fashion
This type of building was first used by the Romans. But then in Europe it found itself in relative obscurity until the revival of high-quality stone construction, caused by Carolingian and Romanesque architecture. The construction method was especially common at the basement level, for example, at Myres Castle in Scotland or at the ground floor level for storage rooms, as at Muchalls Castle in the same country.
It is difficult to construct this structure accurately because of the geometry of the transverse ribs of the cross vault, which are usually elliptical in cross section. Therefore, such painstaking work required a great skill in cutting stone. It was necessary to form a neat dome. It was replaced by more flexible arches of Gothic architecture in the late Middle Ages.
New Design Benefits
The vault of the cross can be rounded, as in Romanesque churches, or pointed, as in Gothic ones. This arched structure is usually made of brick or stone and is designed to support the ceiling. The main advantage of this type is that it takes on the entire weight of the roof and distributes it only at four points in the corners of each rib. This adds strength to the ceiling because all sides of the vault help distribute the weight and support the ceiling.
And if there are such supports, then you do not need to build a solid wall between them. Therefore, it became possible to make many glass windows. So the churches became brighter, and the parishioners in them more felt the presence of sacred forces.
In the early medieval cross arches there were six fulcrum - the corners and ends of another arch. For example, the Laon Cathedral and Notre Dame in Paris used this type. But by 1200, most churches, such as Chartres or Rouen, used cross vaults with four ribs. They demanded fewer supports, which allowed more light to enter the cathedral through the huge windows of those times.
Modern architecture and medieval experience
The ceiling in the cross-dome vault is simply the construction of several vaults in a row. After repeating this structure, the builders realized that they could overlap long rectangular sections of space, such as corridors. The ceiling with a cross vault is one of the most popular and beautiful forms in modern homes. However, the traditional method of construction required for the manufacture of this type of roof required considerable skills, time and material. For example, a small room usually needs at least two experienced carpenters to work for two full working days.
And this is taking into account that you will not include preparatory work, layout, layout, cutting blocks and assembly. In addition, even those carpenters who have the skills necessary to create this ceiling either refuse or charge such an outlandish price that the manufacture of such a design becomes inappropriate.
Civil engineers of the 20th century studied the forces of static stress in the design of the cross arch and confirmed the foresight of the Romans in an effective design that can achieve several goals: minimal use of materials, a wide range of construction, the ability to achieve lateral lighting and avoid structural stress. The most original contemporary design is the Europe's largest Hauptbahnhof railway station in Berlin, which has an entrance building with a glass mesh arch.