Конструкции

Domes and vaults

Dome — the cover formed by a rotating surface. At equal thickness of constructions, it is possible to block greater flights, than flat plates can. In "Our Projects and Constructions" gallery examples of projects of overlapping of big spaces by a structural dome design are presented. In the project of domes of Salekhard we used single-layer structure, diameter of a big dome – 70 m. In the project of "Sphere" cafe structural farms are used. In the 30-s of the XX century Bakminster Fuller developed the well-known spatial design of a geodetic dome — the hemisphere made of tetrahedrons which became one of the largest constructive innovations of the past century (see gallery). For a long time the geodetic dome is known as especially strong design on gram of the used material, which can cover the big areas with use of the economic amount of construction materials.

DURABILITY. The bigger dome is, the easier and stronger is its design (in proportion to change of its size) since the network of geodetic lines offers geometry of the strongest and economic structural system, and the geodetic lattice extends tension in the most economical way of all possible. Uniformity of distribution of loading on a cover of a dome allows to withdraw to 50% of triangles, and use bearing apertures for a frame of doors, windows, verandahs, balcones, winter gardens.

GEOMETRY. The major factor influencing rational use of materials and energy efficiency of a design — is a form. The sphere has the smallest relation of the area of external walls to the internal volume of the building among all figures of identical capacity. The less total area of walls and a roof, the higher is the efficiency of energy consumption on of climate control indoors. Dome houses are very attractive economically, with modern materials and the correct design expenses on heating (and cooling) in them are 70-90% less.

TECHNOLOGIES. The surface of a sphere is approximately one quarter less, than the surface of a cube of the same volume, so and materials for construction of a dome will be required one quarter less. In addition, dome has 60-70% less details in the framework design. That allows to save in addition 5-10% of energy on lack of "cold bridges" because of uniformity of material of protective barriers and moreover to save 40% of time on assembly.

PHYSICS. The positive ratio of the area to volume gives domes amazing thermal characteristic. The area influenced by environment has much more influence on power efficiency of the house, than quality of putty in seams, and thickness of its walls, and heatlosses of the base depend not on the area of a floor, but on perimeter length.

AERO AND THERMODYNAMICS. Heatloss of the building is in a direct proportion to its aerodynamic resistance. The wind smoothly slides over and round a dome, creating insufficient turbulences and funnels to break an interface of air which fastens to a surface of any object intermolecular microgravity. Thanks to aerodynamic effect of a design the wind bends around a dome with a smaller resistance. The bent surface of a dome promotes natural air circulation and effective air exchange in rooms. Natural "ring-shaped" currents of air, prevent stratification, and air temperature remains identical on all volume of a dome, from a floor to an apex. The aerodynamic effect allows to save on heating and conditioning.Rectangular building has high windage. The wind hits directly in a vertical wall, breaks the heat-insulating air layer, creates area of a high pressure. And the lee side of the building is under the influence of turbulent streams and partial vacuum at this time. Turbulences cool the building, and the vacuum exhausts heated air from the room not only through cracks around doors and windows, but also through any smallest imperfections of a design on this side of the building.

The warm air exhausted from the room is replaced cold, through similar cracks, microcracks and micropores. Even in modern houses the cumulative area of such cracks and pores makes an equivalent of an open window. Extending indoors dense, cold air,in addition, cooled due to Bernouli's effect and turns into draft. The design of a dome is deprived of such drafts. Doubling of the sizes of a dome leads to doubling of its thermoefficiency.

Source of formulations: section "Dome House"from the site apxu.ru

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