The material with which to build underground structures, must have a high resistance, water resistance, erode, frost resistance and fire resistance. Due to the complexity of reconstruction of underground facilities, their service life should be longer than the land-based structures, respectively, the materials for the manufacture of such structures needs to be better. Materials which meet such requirement are: steel, cast iron, concrete and reinforced concrete. When erecting concrete structures concrete its hardness should not be less than “B15”, and the thickness of load-bearing elements not less than 20 cm. For prestressed concrete structures the concrete grade shall not be less than “B25”. Mark of concrete on water resistance should not be less than “B-6” for structures located in soil moisture hanged. Estimated supports of concrete in concrete and reinforced concrete structures take accordingly to the current normative document. Continue reading
This is the most magnificent building built by man – the only one that can be seen from space with the naked eye. An impregnable fortification. Symbol of antiquity and power of the Chinese civilization. Heard about it every, but. no one saw it whole!
The construction of the Millennium
Look in any encyclopedia about the great wall of China can be found only a short article. And, alas, the data in different sources will often contradict each other. Nevertheless, officially recognized is considered such a story.
The great wall of China is a chain of fortifications, extending in the North of Ancient China from the Yellow sea to the Gobi desert. The total length of the wall is more than 6500 kilometers. The wall was built over two millennia.
It all started long before our era. At the time of the ancient Chinese state, about which we know almost nothing, collapsed into many small principalities that fought each other. And the richest of them began to build fortifications, so that it was easier to defend their borders. Continue reading
Small popularity of Gothic art in Italy is very interesting due to Italians. According to some theories of art, the novelty of the Gothic corresponded to the aspirations of the Italian artists of the late middle Ages. But the spirit of Gothic art, its formal principles have not responded to the tradition of Italian art. Language and means of expression of the Gothic, a strong urge of cathedrals were up in the eyes of the Italians ambition to nowhere, not having a purpose. Clearly rhythmical architecture, in which was laid the trend of endless repetition, does not respond to the requests of the masters, who are accustomed to see in any work strict proportions and completeness of the composition. At the same time, Gothic art seemed sufficiently abstract but from the abstract and tried to leave the artists-artisans of the Italian communes. Romanesque art of Central Italy at the end of Duecento quite realized the desire for a clear and classic proportions. Continue reading