Scientists Have Discovered The Secret Of The Domes Of Italian Cathedrals
Italian engineers have revealed engineering methods for creating self-supporting stone domes of Renaissance cathedrals. The results are described in the journal Engineering Structures.
Researchers from the University of Bergamo analyzed the masonry technique of octagonal domes of Italian cathedrals, such as Santa Maria del Fiore in Florence, built without the use of supports or other elements of supporting frames.
This is the first such study to provide physical calculations of the structure and explain in quantitative terms the forces that make it possible to build such huge structures without the formwork usually required even with modern technology.
Before this, it was only known that the entire load of the dome falls on the walls of the main building, but it is unclear how it was possible to build a dome without using temporary structures that hold it during construction.
Detailed computer analysis, taking into account the action of all forces with detail down to the individual brick, allowed us to explain how the balance was achieved. Scientists used the so-called discrete element modeling technique, which allows analyzing the structure being built at all stages of construction. Using this method, you can not only calculate the mechanical properties of the finished structure and determine the ultimate equilibrium States and stability of the completed structure, but also recreate the construction technology.
The dome of the Cathedral of Santa Maria del Fiore was built in the XV century by the Italian Renaissance architect Filippo Brunelleschi. During the construction of the dome, a peculiar masonry technique was used for the first time, in which the role of the frame, which provides rigidity, was played by rhombuses of vertical bricks laid with a "herringbone." The space inside the lozenges was laid with horizontal rows of so-called field bricks.
Each such row served as a flat arch, or plate, the final elements of which rested on the end stops in the form of horizontal rhombus bricks and actually distributed the load throughout the structure.
The authors of the study showed that the resistance of the plates prevented the sliding of rows of bricks during construction and the collapse of the stone dome. But the most interesting thing is that the rows of lozenges in the dome of Santa Maria del Fiore and later cathedrals of the XVI century do not go horizontally, but in a spiral that rises to the top of the dome in the form of a line called loxodrome. With this pattern of masonry, the strength of the structure is provided not by the cement mortar that binds the bricks together, but by the location of the bricks themselves.
Scientists believe that the use of such technology will allow the construction of domed structures made of bricks not only without mortar but also without human participation, using robot drones that deliver the material to the place of laying. This method, according to researchers, is not only the safest and cheapest but also the most environmentally friendly.
"The construction industry is one of the most wasteful," the research leader, Sigrid Adriaensens, a Professor of civil and environmental engineering at Princeton University, said in a press release. "So if we don't change the technology, there will be more and more construction waste."